The rhomboids get worked at different angles by chins, wide grip rows, bent rows and behind the neck pulldowns.
I need some clarification...do you work at a desk with a computer all day? If so, you could be tensing up and putting strain on those nasty little muscles in your back between the lats and traps. There are 3 different ones there: the rhombus, the teres and infraspinatus. Try doing some of the exercises I mentioned above with lighter weight, higher reps, and squeeze at the contracted position of each for a few seconds. On the BTN pulldowns, be carefull as this exercise puts some nasty pressure on the rotator cuff. It's great for flexing those nasty guys, but otherwise hard on the shoulder...so use light weight and really control the motion so you can focus on flexing those back muscles. I'd think that if you work those muscles out to get them good and sore, you might be able to relax them during the day in order to get some propery recovery on them. The thinking behind this is that if they're sore, you can concentrate on relaxing them. Otherwise, the stress in your world allows your to keep on going with a tensed up back all day.
I hate to give you advice that might hurt you here bro...so, you have to go with what feels right ultimately.