this can be due to a variety of causes. for example arthritis, however this is less likely due to the sub acute presentation of your symptoms. other possible causes include gout VS pseudo-gout. gout would be much more acute then your symptoms, for example presenting overnight with severe pain and swelling of the big toe. Pseudogout has a much slower onset over days. Both of these are crystal induced arthropathies. Other possibilities might include septic arthritis, however must like being your case because you would have fever if it was infection. there are many other causes, somewhat hard to distinguish without the physical exam/tests. if you have fever, or if it is severe, or even if it s just you re worried about it, I would suggest you visit your doctor to get it checked out. Just to be on the safe side. Besides, getting some medication for symptomatic treatment would be very helpful as well.