Pain in calf

I currently have a history of HBP, Graves disease (treated and now have treated hypothyroidism), Migraines (used to be cluster but now I get @ 2 a month) and Fibromyalgia.

About 9 months ago I was diligently using my treadmill, I started getting a sensation on my calf like there was a hair or something on my leg (only felt it during exercise).  It'd be so weird feeling that I'd actually stop and look to see if something was there.  After a month or 2 that sensation turned to pain in the calf along with an overall tightness of the achilles.  The pain in the calf is usually worse at the beginning or end of exercises - seems to lessen once I get going.  The achilles is very stiff especially in the mornings, it's hard to walk down stairs the proper way.  I'm tired of always being told my aches and pains are my fibromyalgia.  I really don't feel this is the case this time.  The calf pain is now starting to be present even at times of rest.  Any ideas of what this could be?  Thanks.