What Causes Backache?
The basic causes of back pain are the following:

sedentary living habits,
weak abdominal or back muscles,
poor posture,
muscular tension,
straining of the joints
arthritis,
prolonged sitting or standing in one position,
prolonged stooping,
improper lifting of weights,
wearing high heels,
lack of exercise,
after effects of Epidural after childbirth. I suffered from bad backache after the birth of my first child, delivered via c-section (given spinal cord anesthetic).

Remedies : 

The Chamomile Tea Remedy
Chamomile tea is used to treat a lot of different ailments so it really is no surprise that it would work for a backache as well. Chamomile tea can help relieve stress, therefore help relieve back pain. Chamomile tea offers a calming relief to sore muscles. It is used best when taking a break from work or after work to relieve stress and sore muscles. Just steep one tablespoon of Chamomile flowers in one cup of hot water for 15 minutes. You can also buy the pre-packaged chamomile tea. Either way, drink one to three cups a day and it should relieve sore muscles in your back. Be careful though, chamomile contains allergy induced pollens from ragweed. If you are allergic to ragweed, ask your doctor before drinking chamomile tea.

The Epsom Salts Remedy
Epsom salts are another product often used as a home remedy for many things. Epsom salts ease back pain by reducing swelling. When taking a soak in the tub, add at least two cups of Epsom salts and soak in the tub for 30 minutes. Your back will fill a lot better when you do.

The Warm, Uncooked Rice Remedy
Here is a weird remedy for you. I wonder hw many people have ever heard of using warm, uncooked rice as a home remedy for a backache? Take a clean, thick sock and fill it with uncooked rice. Place the rice filled sock in the microwave for up to a minute and apply it to your back. Be careful not to make it too hot.

The Ginger Root Remedy
Ginger root has anti-inflammatory compounds which have mild-like aspirin effects. When you have a backache and you have access to Ginger root, cut a fresh ginger root into slices and put in boiling water. Cook the slices of ginger root on low heat for 30 minutes, strain, sweeten with honey or sugar to taste and drink. This should ease your backache in no time.

Diet for Backache
Minerals needed to diminish and prevent backache include calcium and magnesium. Magnesium is found in all fresh green vegetables, apples, figs, wheat germ, and all seeds and nuts, especially almonds.

Lemon juice in water, up to six glasses daily, benefits the kidneys, easing backache.

General Tips for Backache Treatment
If you are not experiencing acute backache and suffer from backache only seldom, you should anyway pay attention to your back. Follow these easy, but useful tips to prevent back pain:

If you have to sit or stand for long periods of time, do not forget to change your position from time to time.

If you have to lift heavy things, straighten your knees and keep your back straight all the time as you are lifting the load.

Choose a firm mattress to sleep on. Do not sleep face down.

Choose a chair with good back support.

Give up smoking.

Do regular exercises for back, visit swimming-pool regularly or practice yoga.

Nutrition for a Healthy Back
Backache prevention and treatment are also connected with diet. Daily meals of a person taking care of their back should contain plenty of raw vegetables and fruits (except bananas). The backache sufferer should have three to four meals every day, which include, apart from fruits and vegetables, wholewheat products, milk and fruit juice. One suffering from back pain should avoid fatty and fried food, sugar, spicy condiments, strong tea and coffee.

For those, who do not like eating plenty of raw vegetables, there exist many recipes of salads including both fresh vegetables and natural additives, like sauces, oils or cheeses, which make the salads taste very good.

Remedies for Back Pain

Excerpts taken from http://www.geniusbeauty.com/woman-health/backache-treatment-methods-physical-exercises/

If we are speaking about acute, but not chronic backache, the causes of it are commonly poor postural habits. If this is the case, the pain can be lessened by some exercises.

Exercise 1
Sit down on the floor. Bend the knee of your left leg, keep your right leg straight. Put the elbow of your right hand on your left knee from the left. Draw your left hand aside as far as you can. Push off with your right elbow from your left knee, but DO NOT push too much. During this you can feel a little crackle in your spine – this is normal. Make 5-10 pushing repetitions. Do the same to the other side with your right knee bent and your left leg straight 5-10 times. Repeat the cycle from both sides by-turn.

Exercise 2
Sit on the floor with straight legs all the time, while you are doing this exercise. Try to touch your toes with your fingers. Make 10 repetitions.

Exercise 3
Stand in front of the wall with your back turned on it. The distance between you and the wall should be about 50-70 cm depending on your height. Arch your abdomen and put your palms on the wall head-high with your fingers down, so that your elbows are the highest part of you. Walk down with your palms on the wall little by little to the floor. The final position is when your palms are on the floor. Walk back upwards on the wall to the initial position. Do this exercise slowly.

Exercise 4
For those, who cannot do the previous exercise here is another one, which is easier. Lie on your back. Bend your knees. Lean on your palms and feet, arch your chest upwards. Hold for 20 seconds and release. Make 5 repetitions.

Exercise 5
Lie on your back, bend your knees. Press your back against the floor. Do this by only contracting the muscles of your abdominal. Stay in this position for 3 seconds and release. Make 10 repetitions.

Exercise 6
Lie on your back, bend your knees. Raise your shoulders and head so far as you can. Stay in this position for 3 seconds and release. Make 10 repetitions.

If you have to stand for long periods of time and you cannot do exercises, just raise one foot on a platform.

The other exercise which I find really effective in keeping my backache at bay is exercising on my Fitball . This exercise is similar to Exercise 5 above and it focuses on exercising your back by arching your back.