tendonitis
"I had a severe side-effect of naproxen. I had some inflammation in my left knee and it was bothering me with sitting down, so I showed it to the doctor. I was prescribed Naproxen 500mg twice a day for 5 days. I took three tables in 36 hours (making sure after lunch and dinner and with plenty of water) and after taking second pill on the fist day, I had terrible time. I couldn't sleep, have severe funny feeling in my stomach, right under my ribs and just above the stomach. I had strong empty-stomach feeling all the time. The feel for my whole body was terrible and I feel super-sick. I didn't throw up or had loose-motions but had lots of stomach pain and extreme heart-burn. 

I stopped taking medicine after 3 pills and informed my doctor."