My fingers lock all the time. It can be very frustrating when you're constantly dropping things.

Its strange because its only my right hand and the pinky finger.

Surgery was the best thing I could have done! Try to make a fist and your fingers will not bend or if they did they get locked/stuck and it hurts to try and "pop" them out. Sometimes it would go away, perhaps try what people have suggested above. But when it does not work surgery was my answer. I wouldn't be able to type right now if I didn't have it done. Good luck!

I am not sure what you mean by locking, but my hands cramp up so terribly at times that they look contorted. It takes a few minutes or even longer to stop the spasms. During the spasm I would definitely say my hand and the fingers are locked up. I was told to take more calcium, magnesium and potassium and drink OJ or eat a banana when this happens. Was also told to stay hydrated.

Trigger finger happens to a lot of people without MS, so be leery of attributing it to MS.