I’m on Allopurinol, too. Several years ago I would periodically have these episodes where out of nowhere I would wake up and not be able to walk. My foot would be swollen and the pain would be in the top my foot in the joint where the foot meets the leg. It would look like an injury but an injury hadn’t occurred. After a couple days rest it would get better. This would happen every few months.
After about the third time this happened I went to see a doctor. The symptoms were so different than traditional gout she didn’t even do a blood test to rule it out. I got x-rays which showed nothing. Finally, around Christmas in 2016 it happened in my knee. Same deal, pain and swelling. I went to see a different doctor this time. He drained my knee and tested the fluid that he drained. Sure enough it showed high levels of uric acid. He started me on Colchrys and then eventually switched me to Allopurinol. I haven’t had a flare up since. But my symptoms are unlike any I’ve heard with gout. It has never attacked my big toe. I don’t experience a burning sensation or redness. It looks and feels like an injury. Like a really bad sprain or torn ligaments or something. Sometimes I still feel weird calling it gout but ever since I started the medicine 5 years ago I’ve been fine.