How soon could i expect results from [hysical therapy for sciatica/s.i. joint pain?

Varies: That is a very difficult question for any physician on here to answer. Many factors need to be considered such as appropriate diagnosis of the symptoms, severity of injury/pathology, cause of injury (ie inflammation vs structural), durations of symptoms, premorbid condition, social hx such as smoking, type of therapy implemented, etc.Key to therapy is your diligence and appropriateness of therapy!

Not Known: Nothing can work fast, however if PT can relieve pressure on the spine where the nerve is getting pinched or the SI Joint gets relief than pain relief can occur. If you are not improving after 2-3 weeks with regular therapy sessions, I would suggest seeing a pain/spine specialist to see if a cortisone injection might be helpful.