I am not a doctor. I do have bad tendonitis called plantar fascitis and it feel like that. It hits after I have been standing a lot. It feels like my ankles are breaking. It can go up my leg. I wear braces on my ankles when it is acting up. I freeze a small water bottle and roll it under my foot for ten minutes several times a day. I was told not to go barefoot even if I get up to go to the bathroom. They gave me steroid shots in the heel but they did not work in my case. It can take a while to get over.
Alex
I'm saying that this is what you have, however is sounds like Achilles tendonitis, I have that in both R & L, when you first get up it's painful and after the muscles are active it feels better but still hurts. I was told it's not related to my M.S.
I try to ice three times a day !!
Currently I have a walking boot for the next six weeks, If you Google Achilles tendonitis you'll find some great exercises.
Thanks for the information. I will talk with my doctor about both of those conditions. It got so bad last night I felt like I had a cast on my leg. It felt numb, stiff, and achey all at the same time. It feels much better this morning though.