I think this one's still up in the air... but I have been diagnosed with MS, and my main, 'always there' symptom has been migraine-like head pain. In fact, I actually dismissed my symptoms for years as migraine, only to find out that I have MS and Trigeminal Neuralgia.

I was diagnosed as having migraine however at age 6 (MS diagnosed at 31). The Trigeminal Neuralgia was diagnosed 1 year prior to the MS.

55 is not too old to be diagnosed with MS. It's not as common, but it's not unheard of either. I do hope that you don't find out it's MS.