Here you can find one of the most common reasons of the left side back pain:
This is very common. When you are standing or sitting in an incorrect manner or there are some orthopedic troubles with your feet all that together can lead to develop lordosis. And that can be a direct reason of one side back pain as well. Then you should start some physiotherapy to get feel better.
Back pain during pregnancy, especially on the left side, is a very common problem. There are few reasons why such pain can appear. First of all the growing child and growing uterus can make some extra pressure to a delicate body structures including several nerves. Besides it some hormonal changes in a body of pregnant women can make her to be more sensitive for any discomfort in her body. Moreover uterus and a baby are heavy especially at the end of pregnancy so it is perfectly normal situation to feel back pain and it can be also on the left side.
As it has been already mentioned above problems with kidneys can give a painful feeling not only in the abdomen area, but most of the time you will experience very strong pain in your backs. Depending on which kidneys there is infection it will correlate with the same side of your back. But there are many medications that can bring you relief.
As you can see many different types of reasons can lead to the left side pain. It can be also leg pain, arm and hand pain, also head pain on the left side is possible.
Home treatment can give you some rest for a while, however most of the time you need to consult your health problem with a doctor as a serious left side pains can be a first signal of a dangerous disease.