Joint pain has certainly been a feature of my illness over the years. This happens in multiple joints but I have particular difficulty with my hands, including the finger joints. Sometimes just one joint in a finger and sometimes multiple joints in the hand. Sometimes inadvertently "catching" the joint(s) when pulling on clothing or moving bedding is really sore. Sometimes the joints seem weaker or more unstable.
If you have had ME for a while and this is new to you it might be worth getting it checked. Things they'll want to know include:
1. Is it worse 1st thing in the morning and does it then wear off?
2. Does movement gradually make it better or worse?
3. Is there any redness or swelling about the joint?
4. Does it hurt to touch the joint?
It might also be worth considering if you have made any changes to your diet or medication lately.
Hope you get it sorted. Let us know how you get on.