Knee Injury

Good evening folks, I just discovered this website and hopefully I'll get some answers here.

Mid june just passed I had a bad fall carrying a keyboard while on vacation in Georgia USA. I do know I hit the inside of my right knee off the road and I assume I twisted it during the fall. My right knee was very painful and super swollen.
For the next three days I rested it,applied ice and took ibprofen. When this didnt work I went to the ER who x-rayed me (didnt show any fractures), said I'd a "Contusion" and was given 800mg of Ibuprofen and Lortab for pain. Four days later I returned to the ER as the Iubprofen was killing my stomach.
The ER doctor drained my knee (half pint, blood stained) and give me Dolabid and Lortab.

On my return to Ireland my own doctor give me Difene 100mg once a day but they didnt help. I also saw a consultant who put my name down for an MRI. I returned today to see a different doctor at the clinic in the hope he'd drain it. He refused as he is'nt 100% sure what is wrong. He suspects I've a loose body in my knee and give me 500mg of mefenamic acid. However I have been getting chest pain which must be down to the drug. Has anyone ever had this side effect from this drug?

Can anyone reccommend a good painkiller that I could suggest to my doctor? Lortab is great but Irish doctors won't hand it out so easy like the Americans do!.

My symptoms are a super swollen right knee, Locking of the knee(can-not straighten or bend it backwards), also have sharp pain, esp at the inside site. Pain level when bad is 8/10.