Hi
It is generally due to stretching of
nerve due to abnormal posture while sleeping.
You can have restriction of arm with shoulderbinder and arm sling for 3 to 5 days. Along with this you can apply ice and pain killers. After 5 days you can start exerise and stimulation. If this does not help do ncv emg investigation and
mri of upper limb for
brachial plexus. Then consult brachial plexus surgeon.
Get well soon.
Thank you.