From your description it sounds that you may have a ganglion cyst at the affected joint. This is from the issue that covers the joint space and fluid from within the joint. This is likely what is going on.
I would recommend that you have this checked by an orthopedic specialist.
Is it dangerous?
It may be that this cyst may cause some nerve impingement and this may be why you have the tingling sensation.
No, it is not dangerous.
Are there different types of orth spec.? Or is that what I look for in the phonebook?
You can check to see if the specialist does work on hands. Not all orthopedists do this type of problem. This is not a subspecialist per se but just that some of these specialists will take more of an interest in this area.
That sounds like the answer I was looking for Thanks!
Any thing else before I go?
You are welcome! Good luck!