Have pain in back and left knee had a MRI on back it says disk degenerate disease in L4 L5 I am on pain management I still have a lot of pain don't sleep well, can only lay on my left side cause if I sleep any other way I get parylized. My left knee gives

See a physician. It sounds like your condition is worse than degenerative disease at l4-5. It sounds like the nerve in that area is being compressed. You should see a spine specialist for an accurate diagnosis and management. Epidural injections can often be helpful for these conditions, though if your weakness is profound, surgical intervention may be required.
The. The nerves from our spine run down our legs, so the pain in your leg may be related to your spinal pain. Having your leg go out and having difficulty walking are very serious symptoms and must have a complete evaluation. It might be reasonable to get another opinion on your MRI since your symptoms are so severe. Please have evaluation by a neurosurgeon for your symptoms. If you develop weakness or changes in bladder or bowel control, you need to be evaluated emergently.