as you are a basket ball player , swelling in right knee not in left, probably you should first think of un noticed trauma causing Intra articular injuries. Get your self checked ind investigated for IA injuries.
Other causes also to be excluded such as infective , autoimmune and gout
and non specific arthritis
First go for X rays, MRI
and routine blood test
this is brief plan for your problem written in few lines
Dr Niraj garg