Hello Marsha,
What was the reason for the initial decompression if you know? If it was due to bony abnormalities in the acromion perhaps this is regrowing and causing the same symptoms? Or maybe one of the tendons/bursae has become inflammed and hence mimics the symptoms you had before? Perhapps it is scar tissue formation however you may need to get this checked out to be sure what exactly is going on.
Do you transfer yourself in/out of your chair independently? If so then I would strongly suggest you get your shoulder looked at asap, because if it gets worse it may impact quite significantly on your everyday life if you're no longer able to transfer.
I hope this is of some help, do let us know how you get on!
Ruth Cheesley BSc(Hons) MSc MCSP
Chartered Physiotherapist