I had a cavity year and half ago and the dentist that I used to go to just looked at it and cleaned the cavity and put some fillings in there. Then when I came back for another checkup, he was start working on the cavity teeth like I needed a root canal and made my teeth short so he can put a crown. Is this how a cavity is done by cleaning and putting a crown in? I don't think he knows what he was really doing because he didn't do a full examination like an x-ray on the teeth to see if I really needs that procedure or any simple examination except looking at it.. so anyway he drill my teeth short and put a crown on it and now it has been a year and half and the teeth with the crown has been hurting sometimes and when it hurts, I feel pressure from my jaw and sometimes from other tooth. So what I do is put something in my mouth to stop the pain and pressure. Did the dentist do something wrong? Should I do something about this tooth? Please help.

Sounds like you now need a root canal

You may need a root canal but an x-ray would be needed to confirm it.

you need to go back to you dentist and tell him this you demand a x-ray to see what the tooth looks like underneath the gum line and to see what the nerve looks like ask if the tooth has an abcess if the tooth does have an abcess you need a root canal which yes they can do with the crown on it the dentist will access a small whole in the tooth to perform the procedure and then he can put a composite ( tooth color ) filling in the whole. If the tooth structure seems to be fine no abcess then ask the dentist how the bone support looks that is if the gum tissue is recedded or not ask the dentist if the tooth is mobile (loose ) if it is loose you may loose the tooth with an extraction. If the tooth is not loose that is good then. I'm a dental assistant for 15 years I know what I'm talking about.