Having a wallet it in your back pocket could you to have a low back pain contribute like sciatic nerve and what can be done?

Yes. Exercise.: Sitting with a wallet in your back pocket is a common way to cause back pain. This "tilts" your pelvic bones and causes strain to the muscles and ligament of the back. Same would occur if you were to walk with one shoe taller than the other. Best practice is that this shouldn't be done. Also, strengthening exercises (see my health tips on back strengthening) will also prevent and lessen pain.

Piriformis syndrome: Its the george costanza problem. If you have a large wallet in your back pocket it can cause pressure on the sciatic nerve, also called piriformis syndrome. This mimics sciatica from the low back, but usually worsens when sitting and relieved when standing. Remove the wallet, try nsaids, physical therapy, and sometimes piriformis injections work as well.