Pain from left buttocks down to foot, goes tingly and feels cold. sometimes where the pain inside it feels warm, feels like some1 punched my thigh. pain is when i sleep or sit, leg feels swollen even tho its not ?

Nerve pain: BriB352 - this sounds like a nerve related issue related to your positioning. Nerve compression can occur either in the spine or along it's path down your leg and is often influenced by the physical position you maintain (laying down, sitting, exercise, etc). Symptoms may resolve with a position change. If not, seeking evaluation may be helpful to identify where the issue is(central vs.peripheral)