If this was always the case after surgery, it might be due to asymmetry in the pocket dissection. If you were initially symmetric after surgery and this has been occurring since that time, you could have early capsule contracture and require treatment for that. You should check back with your surgeon.
Difficult to determine if you have an early capsular contracature or just implant malposition. An examination would be necessary to differentiate the two problems.
It appears you are developing capsular contracture. You need close follow-up at this point. Your PS can decide if other intervention is warranted.
Thanks for your question-- The size and shape discrepancy you describe could represent a capsular contracture. The fact that one breast feels firmer lends more credence to this diagnosis. Singulair may help, but is FDA off-label for this condition. It's best to keep in contact with your plastic surgeon, and if this does not improve, you may need exploration, capsulotomy (release), or capsulectomy (removal of the scar capsule), and other methods to decrease your chance of capsule. These include textured breast implants, possibly the use of an acellular dermal material can make capsular contracture less likely as well. Best regards,
-Erik Hoy, M.D.
The most common cause of a firmer higher tender breast after breast augmentation is capsular contraction.
However it seems as though your plastic surgeon is following you carefully and you need to follow-up with him or her in follow their advice. If it turns out you do have a capsule a capsular release or capsulectomy can be done.