Is it normal to be in pain for the last two months, after having a root canal and crown?

I had a root canal and a crown placed immediately after, two months ago. The dentist has reshaped multiple times the crown to rule out possible biting issues. Though this has not fixed the discomfort pain at all, my tooth (no. 15) is still in-pain. I feel pain/discomfort when I bite or apply pressure to it. Does anyone have any ideas of what might causing such pain/discomfort? Thank you in advance. Panos M.