I wouldn't want my immune function lowered for any amount of time.
I only know the natural things that you can do, sorry! I would suggest starting with using heat. Sometimes that's enough to ease it up. A heating pad or a rice sock (
www.wikihow.com/Make-a-Rice-Sock - although I use a larger sock than they show) work well for many of our aches and pains.
You can start on turmeric or curcumin (a turmeric extract), which will lower inflammation and thin the blood slightly.
There are more 'powerful' natural things that you can use to thin the blood if that's the reason for the pain, but I would really recommend trying the above things first, as it may not be a fibrin issue.
Natural things to thin the blood (reduce fibrin) are serrapeptase or nattokinase.