Please Help! Root Canal Problem

[iloya]

I had RCT in my lower right first molar 3 years back.  I am a tobacco addict and used to chewing tobacco.  It had taken a long time for the completion of the process since there was an infection that was not healing properly.  Finally, my dentist filled up the canal and fixed a crown bridge over my first and second molars.  The 1st molar with RCT was sensitive to cold fromt he beginning however after sometime the pain subsided.  I guess I had to adjust my biting habits to evade the occassional pangs of pain that shot up. Also, I used to sense pain when metal touched the cap. Few months back I visited another dentist (since I moved from that city) for scaling and I had severe pain in my molar after scaling was over(I had told that guy to watch out the RCT one yet he maintained that it didn't matter and I literally felt cement falling out when he scaled under the capped molar).  The problem worsened and recently I got the crown(bridge) removed because I felt that  the bridge had loosened and there was a risk of decay underneath.  
As expected there was some decay and I asked my dentist to make two seperate crowns instead of a bridge because I didn't want to risk my other good molar.   The dentist told me that he needed to cleanup since there was some decay and he drilled around the molars and took measurements.  Since then, I have been feeling severe pain shoot up on the right side of my lower jaw  making it almost impossible for me to even work.  I take brufen and the effect lasts for 6-7 hours and again the pain is back.  I visited the dentist today and after X - Ray he said that there is an infection and that my tooth should be removed and he also recommends RCT in my other molar.  I dont trust that guy any more. Please help and give me guidelines as to what should be my approach with another dentist .
Thanx in advance

[iloya]

OK I visited another dentist who inspected my molar first with finger pressure and  X-Rayed my molar after I said that I could not feel pain in gums but rather felt pain shooting from underneath the tooth.  His diagnosis was that I  have developed an abscess in the root and has prescribed me an antibiotic.  He has said that  the filling will have to be opened up and he will attempt a cleanup after 3 days and that there is no need to get the tooth removed.  Now my question is that after cleanup should I go for a bridge or seperate crowns in order to avoid risking my other molar as well???