A good exercise (not musical, but physical) that works on the piano, is to hold down one finger whilst taking it in turns to play the other 3 (in the case on not using the thumb). So hold down the first finger, then play 2, 3, 4, 3, 2 on your chosen notes. Then hold down 2, whist taking it in turns with 1, 3, 4, 3, 1. Just a good little exercise - only a couple of minutes to do at a time. You can incorporate it into a fragment of a tune such as Amelie: hold the first note of each phrase while doing the filigree stuff. On a G/C it would be D efefe E efeCe B deded A cdedc (the little notes are in the lower octave to the Capital notes. In D/G terms I guess it would be A bcbcb B bcbGb Fsharp ababa E gabag
Just a small thing to work on. Discard if it doesn't help.