I have tmj. lately i've been getting maybe a tmj flare? i'm getting facial pressure and tightness in my cheeks and jaw like a facial headache as well as jaw pain, cramps and spasms. also my teeth are aching at times. can tmj mimic sinus type symptoms?

It sounds as though you have either TMJ syndrome and/or sinusitis. See your dentist for both for correct diagnosis, and see this link for information about sinusitis: https://drneilmcleod.com/information-sheets/

Most likely you are having an exacerbation of TMJ dysfunction, and suffering radiating pain over the face. This can be sorted out by a direct physical examination. To exclude sinusitis, a CAT scan may be necessary.