I have a pinched nerve in my neck which caused muscle weakness/atrophy in my right triceps and pectoral muscle. is it possible to regain my strength?

Yes, but: Once the nerve has been decompressed by a surgeon there is a chance that the nerve will regenerate. This is a slow process and will not be immediate. If the nerve was permanently damaged then your strength might not come all the way back. Good luck.

It is possible.: The pinched nerve usually indicates the herniated disc compressing nerve roots, C7 in this case. Anterior diskectomy and fusion at c6-7 level will improve motor funcition.

Aggressive theray: Depending on the duration of nerve injury. Sometimes getting an EMG and nerve conduction test can tell if your nerve is regenerating. Aggressive physical therapy can help.

Yes : If the pinched nerve problem is resolved and physical therapy is started with specific exercises to rebuild the muscles in the area.