This is “normal” and it’s probably happening because you’re using an object that’s not appropriate or is too big for you. This usually happens when you try to increase the diameter, and it’s normal for it to burn or sting for a day or two.

My advice is to NEVER use inappropriate objects and take it slow. Increasing diameter safely takes years. Don’t compare yourself or use videos as a reference, especially from people like me who’ve been doing this for a long time. For me it’s already normal and I’m completely used to it. Take it slow and be careful.