It sure sounds a lot like shingles. Have you seen your doctor? I'm not sure if the rash always presents in everyone. I do know there's a medication they can give for shingles that helps. I forget the name of it but I know they gave it to my mother. Even after the rash (if you get it) is gone, shingles nerve pain can last a long time.
Good rule of thumb is that if you have something nagging at you for more than 2 weeks, see a doctor. Of course, more acute things need immediate attention but in general, if something doesn't go away in a week or two, you need to get it checked out.
It most definitely IS possible for people to have shingles without having a rash. The pain is just as intense as it is in those where the rash is present. The area that you are describing as being involved on your body is CLASSIC for shingles. The pain and/or rash follows a nerve root from the spine around to the center of your chest.
I would let the doctor know what is going on. Normally shingles is not dangerous unless it is on your face near your eye (it CAN cause blindness) or if you are elderly (over 65) or if you already have a compromised immune system from something else, but in the event that this IS shingles, at least your doctor will be aware of the situation should it get worse or appear on other sections of your body.
I hope you feel better soon! Shingles is VERY painful!