Can an uneven chest be corrected or less noticeable with muscle growth after a gynecomastia surgery?

The pectoral muscles are not usually involved in gynecomastia surgery.  Once your plastic surgery approves you to workout at the gym, you should be able to build those muscles with body building exercises. However, the larger/stronger pecs may not fill out the "empty spaces".Kenneth Hughes, MD, Board Certified Plastic SurgeonLos Angeles, CA

Yes, muscle growth can sometimes help improve the appearance of an uneven chest after gynecomastia surgery, but it might not fully correct the unevenness. Here’s a bit more detail:
1. Muscle Development: Building up the chest muscles through strength training and exercises like bench presses, push-ups, and chest flys can help improve the overall appearance of the chest. Well-developed pectoral muscles can create a more balanced look, which might make any residual unevenness less noticeable.
2. Surgical Considerations: If the unevenness is due to differences in the amount of tissue removed or post-surgical asymmetry, muscle growth alone may not fully correct this. In some cases, additional surgical revision might be needed to address persistent asymmetry.
3. Consultation with a Surgeon: It’s a good idea to consult with your plastic surgeon or a board-certified plastic surgeon to discuss your concerns. They can evaluate your specific situation and recommends on whether additional surgical options or a targeted muscle-building regimen would be most effective.
Overall, while muscle growth can improve the aesthetics of your chest, it’s essential to set realistic expectations and discuss all available options with your healthcare provider.

When the surgical procedure results  in uneven  breast,you should wait for 6-12 months to see the final outcome.Sometime there is a need for additional surgery. 

Sorry to hear that you have concerns after your surgery.  Unfortunately, I think it is very unlikely that building muscle will correct contour irregularities or asymmetries after surgery.  Think of the pec muscle as the mattress and the skin, soft tissue, and gland as the blanket and sheets.  Filling the mattress isn't going to make the blanket and sheets rest smoother.  Know that at 3 months, especially with secondary surgery, you are probably not looking at your final result.  Make certain to follow up regularly with your plastic surgeon and be compliant will all their recommendations to optimize your surgical results.  Best of luck!