Tooth pain to heat and (regular food one day)

Hello,
Over a year ago I had a crown done b/c of tooth pain from a tooth that had chipped and a piece fell off. It was causing me pain after the crown had been put on and I went back to get it ground down as it is a fairly large crown. I am experiencing pain in a tooth to heat but one day I ate a bananna and I got the same pain. I have a crown and the teeth on either side of the crown pain me when the dentist taps them. I just cannot tell which tooth is causing me the pain. I eat hot food and sloup delibaeralty to try adn detect the pain and do not know which one NOR do the dentists. Sometimes it feels like it could be any one of the 3 teeth. My x-ray did not show up anything but the think it might be the crown but they said if it should break or chip by doing a root canal through it which they have suggested then  a new crown will have to go on which is fine but only if there is enogh tooth underneath and if it does not break off due to doing a root canal thorugh a crown. Then if that happens there might not be any tooth for a new crown and then the tooth will have to come out. It is a noticeable tooth and I do not have money for a bridge or an implant but right now not knowing wich tooth is causing this pain is really concering me especially as I have no dental insurance and they said all 3 teeth could be giving me problems. How does one know for sure which tooth is causing this pain and is there a good test I or they can do while checking each tooth. I tried putting a cotton bud into hot water and lookingin the mirror but still no effect. I feel it could be my very back tooth sometines or the root canal I just dont know. he gave me antibiotics but i forgot to take them all. Maybe i should start them over for a few days and finish them out. any suggestions as to what is going on and how can I find out which tooth or how can they. I have been to an endodontist and he cannot tell which tooth either.----thanks for any info. please.

[Ramin Mehregan, DMD]

Dear Nicky
I would suggest you find a reputable endodontist  (root canal specialist) and have the area checked out. There is also the possibility your bite could be off and your are hitting that particular tooth in a pathological bite.
Sincerely
Dr. Mehregan