4 year old crown pain - do I need a root canal?

I am 34 years old and about 3 months ago I had a crown placed on my upper molar. No root canal. It was due to a large filling and gap between the tooth when I’d floss and food would constantly get stuck. I also had a crown placed on the bottom molar directly below this new crown about 4 years ago. Originally, when the new upper crown was placed I had some pain with biting hard food so they adjusted the bite. I’ve had the bite adjusted at least 4 times on the top molar since. The top new crown feels fine now but honestly I’ve been avoiding eating on that side so it could still hurt with hard food and I’d have no idea but My issue is with the 4 year old crown directly below it.. after a month of the new crown the bottom crown now hurts., only when pressure is applied like if I were to push my finger on it or try to eat. I recently had the upper crown adjusted again on Thursday and they did an xray on the bottom teeth to make sure I didn’t need a root canal. They said it looks fine but if it doesn’t get better then I might need one on the 4 year old bottom crown directly below it. Could my bottom crowned tooth just be bruised from the top crown causing pressure even if the top crown feels fine now? I have a mouth guard but lately that’s been hurting my bottom tooth too. Do I just resort to the root canal.. will that resolve the pain? He told me to wait 2 weeks but I’m losing hope.