Having lot of pain in right leg pins needles off and in right foot and back of thigh can be siatic nerve. low back better how can treat the nerve ?

Physical therapy : Physical therapy can be helpful. Gentle stretching and anti-inflammatories help as well. Please see your primary care provider to be evaluated and start treatment.

Varies: I agree that it sounds like it could be a "sciatica" in which a nerve in the back can become irritated and cause pain that runs down the leg. Some cases will get better on their own. Medication can help; physical therapy or chiropractic care can also be an option. If it does not get better at some point, an mri is a test that will likely show if it is coming from the spine.