painful head nodules

I have been having painful head nodules for about 6-7 months now.  At first I noticed a lump on my head about the size of a .50 piece.  It came mysteriously and was gone in about 2-3 days.  It was painful to the touch--felt like I'd been hit on the head with a hard object.  Most reccently, I have had more than one at a time, usually two and they are more painful, larger and don't go away unless I take mega doses of Advil  My doc suggested 2400mg per day)  One of them, slightly above the temple line and a few inches into the hairline--has finally gottem less swollen.  They change in size, pain level and location.,  I've had blood work done and they were no signs of infection anywhere, altho my RA factor was 150.0.  I have NO symptoms of rheumatoid arthritis.  It feels like someone stretched my scalp and I have pain when I touch them.  I feel like I have a headache "from the outside in" if that makes any sense.  My doc wants me to see a rheumatoid specialist and a dermatologist.  Does anyone out there have any ideas of what this might me?    I am desperate to find out what is going on!!  Thanks,