Dear Mary:
Sorry that your having these headaches. As with most headaches, one needs to rule out the other possibilities. Assuming that everything is normal, lab work, MRI, etc. You do not mention any other symptoms like tearing, pain just surrounding the orbit or temporal area, nasal congestion, rhinorrhea, or eyelid edema associated with the headache (making SUNCT or paroxysmal hemicrania unlikely). I think you might have idiopathic stabbing headache (actually a classification of the international headache society). These types of headaches effect females more than males, they are stabbing in quality, can be severe, affect any part of the head, last only a few seconds, and vary from none to many a day. However, it is possible that your rheumatoid arthritis might be playing in this also. Just a thought. It is difficult to tell you for sure over the internet.
I hope I have helped.
Sincerely,
CCF Neuro MD