I have a continuous pain at my right hand joint. i play badminton. how could i get rid of this?

Depends on the cause: It really depends on the cause of the pain. It may be something simple such as a tendonitis which can be easily treated.

FInd a new sport: If the pain is where you hold the racket then you either have to adjust your grip, or pad the handle. If it's elsewhere then you need to be examined by an expert who may take x-rays to diagnose the problem.

Tendinitis: Constant pain like this is probably due to over use tendin inflammation. Try resting for a week or so. Use some anti-inflammatory medication and get a wrist splint. If they don't help, get it checked out by a hand surgeon or your doctor.