I chewed on root canal tooth, no crown.

I have lower jaw pain and neck pain. my dentist suspect a root fracture on lower first molar and told me to extract it. couldn't see fracture in x-ray. I went to Endo and he couldn't spot any tooth fracture. he wanted to do root canal since I have tooth sensitivity on that molar to cold and bite. I did root canal 3 weeks back. still the same pain and symptoms in jaw and neck . went back to dentist to get crown. he is not ready to do crown and saying that tooth could be the culprit for my pain and don't want to aggravate the root fracture if it's still there by doing crown. he said to check back with Endo again.also sent me to tmj specialist to check if its tmj or eagles syndrome.i went to tmj specialist and he did some tests. he gave a cotton roll to chew on that side to see if it hurts after chewing. I chewed cotton roll on that root canal tooth harder. will it cause any harm or further damage or any fracture to the root/tooth? please let me know if it's ok to chew on root canal tooth