Tongue sore like I bit it but didn't. Ear hurts a little too. Been to ENT. Seen nothing. PCP says tmj. Could this be cancer? No swollen nodes or sores

Anything possible. But you have already been extensively evaluated without discovery of anything suspicious, and a proposed diagnosis has been made. Cancer is highly improbable - but if you are a drinker, smoker, chew tobacco or have HPV infection you should be rechecked with regularity, perhaps yearly.
TMJ? TMJ? Could be. Sometimes the symptoms you describe are difficult to diagnose. Follow up on your PCP suspicions. See an oral surgeon. If he confirms TMJ likely, see a TMJ-orofacial pain specialist. Ask for referral from oral surgeon.