I have a dull aching pain in my lower back (left side) i have numbness and tingling in my left thigh down to my knee. ?

Sounds like sciatica: Sciatica is caused by a pinched nerve in your spine. It usually presents as a back pain with radiations down the buttock onto the back of the thigh into the lower leg. Depending on the nerve irritated, it can also radiate to the front of the thighs. Another possibility is arthritis pain to the facet joints of the back that cause a radiation to the back of the back, and back of the thigh.

Unpinch the nerve.: Sounds like you have a disk herniation. As long as the pain is tolerable, and you do not have progressive increasing weakness, or lose the ability to control the bladder or bowels, the vast majority of disk herniations can be treated without surgery. I recommend you get a good exam by a spine specialist, then follow instructions on use of medications, stretchs and activities modifications.