Painful dental crown and bridge?

[dgtlor]

4 yrs ago I had a bridge placed in the upper rear of my mouth, three teeth involved. I also had a full crown/cap placed directly below, one full while the ajoining tooth received a "top half crown/cap" only. No root canal was performed on any of these teeth.
I have had occations when I bite down too hard in this area and feel pain, mostly when I am eating chips or steak. I also have pain in the capped/crowned(?) teeth when I start a strenuous activity such as running or heavy lifting, pushing or pulling. Should these teeth have had root canals, and what should I do at this point? Thanks for any suggestions.