J.,
I understand your pain. I was first diagnosed when I was 6 months pregnant with my first child. It lasted 1 1/2 yrs and started a month after the birth of my second child. There is a more formal name for the syndrome, though commonly known as "new mother's syndrome" the syndrome is not common at all.
Thankfully when I started experiencing the pain my doctor knew exactly what I was going through and schedule physical therapy for "temporary relief (because that's all you are going to get...all 2-4 hours of relief).
Accept what you have and start taking preventive actions. Along with the therapy, I will advice you to use hot water on the area(s) if you were not able to tolerate the pain. I also had to wear wrist braces every single hour of the day with the exception of when I definitely had to have them removed. (Did I mention that both hands were affected?)
Also, you have to be careful when carrying your precious baby. Our instinct is to lift from under the armpit you have to find other ways to carry your angel.
By the way, if your husband or significant other starts to experience the same pain, don't laugh because men go through it as well. The men I have talked to so far used pain medicine rather than therapy and braces.
I hope this helps you out. Just remember that this could last up to a year, make sure you are wearing your braces and use hot water, and if the pain becomes intolerable, please ask someone else to hold your little blessing (child) or put him or her in the swing for the time being.
Good luck to you.
Mother of two precious angels.