How to fix flat and wide breast after a reduction and lift?

Thank you for your pictures.  Your result is more than acceptable.  You could have more tissue to reduce the weight of the breasts.  In my opinion  I would not recommend implants.  You must adjust your expectations about have breasts that don't move especially during exercise.

Yes, revision can be done to reshape the breasts. In my practice, I recommend that patients wait six months to one year, ideally. Breast reduction is one of the most patient-gratifying procedures performed by Board Certified Plastic Surgeons. Follow up at regular intervals should take place to monitor post operative changes and plan any revisional procedures. 

It looks like you are very early in your healing process from you breast reduction. good luck with your results.

You are still early in your healing process, and need to give yourself time to heal. At 6-12 months, you might discuss with your surgeon about any concerns. Breasts do jiggle when exercising unless you are wearing a tight sports bra. You appear to be nicely lifted.