I'm 32weeks pregnant & having extreme lower back pain and can't turn properly or get up from bed.what is the cause & what can relieve the sharp pain?

Back pain: you baby and uterus are pressing against your back: warm heating pad will work and try changing your positions, even lying on your side. No medicine please.

This can occur with : pregnancy just due primarily to the altered proportions and loads caused by the pregnancy especially in later stages. First one should make sure that there are no other causes like a kidney infection but once this has been determined to be just back pain simple things like a pregnancy harness as well as applying heating pads can help as well as seeing a physical therapist to learn some techniques.