I AM DIABETIC AND HAVE BEEN HAVING SEVERE PAIN ON

I AM DIABETIC AND HAVE BEEN HAVING SEVERE PAIN ON MY RIGHT KNEE FOR THE LAST RWO MONTHS. I HAVE TRIED DIFFERENT MEDICATION BUT THE [PAIN AND SWELLING ARE STILL PRESENT ESPECIALLY WHEN I MOVE> tHE LAST VISIT TO A NURSE PRACTIONER I WAS GIVEN DICLOFENAC TABS 75 MG BUT THEY HAVE HAD NO EFFECT> PLEASE LET ME KNOW WHAT COULD BE WRONG AND WHAT I SHOULD DO!!