Left implant hasn't dropped- 3 years post op. Is there something I can do, or am I going to need another surgery? (Photo)

From your pictures and the description you give of your implant moving upward during exercise, I would deduce that your implants are below the muscle.  Implants in this position are trapped inferiorly by the bottom of your pectoralis muscle, and therefore cannot move down.  A second surgery to reposition the implant downward is necessary to get symmetrical breasts.  If you were my patient, I would do a periareolar incision to get complete control over the entire breast pocket.  Your implant is in the complete subpectoral space.  It needs to be removed.   A scaffolding such as Seri needs to be placed to prevent the new implant from traveling into the shoulder area, and then a new implant placed in the partially subpectoral (dual plane) position.

This
long after your initial surgery, it’s highly unlikely that your left implant
will change position any further. There is some asymmetry there, but an
experienced breast implant revision surgeon should be able to give you results
you’re happier with. There are several approaches that can help, possibly
through a capsule release on the higher implant or a lift on the lower breast,
although it’s impossible to say without a physical exam. If you do decide to
proceed with breast revision surgery, it’s important to remember that improvement
is the goal rather than perfection.

While it is difficult to give specific advice without looking at your preop images to assess for symmetry and breast or nipple position, or having the opportunity to examine you in person, from the images that you show and your description of things, I think you are absolutely right, there is something that is amiss with your implants.  This kind of thing can happen in the normal course of events with breast augmentation, so it is hard to be critical of your surgeon just on that account, however, the one criticism that I can make is that if he or she in fact told you to wait this long before determining if the implant would change or not, or if he or she in fact thinks "they're fine," I disagree.  There is clearly asymmetry of the breasts with superior malposition of the left implant, and if they haven't changed by now, they aren't going to.  In fact, I would venture to say that if they didn't change in the first six to nine months they weren't going to, and that is even on the long side.  If you wish to correct this deformity and asymmetry, you will most likely require another operation to remove part or all of the capsule on the left together with repositioning of the implant and possibly changing implant volume altogether to achieve ideal symmetry, if necessary and desired.  While this current situation isn't a medical problem, as you have pointed out it does create an obvious aesthetic deformity, and it is uncomfortable.  If you can't get your current plastic surgeon on board with listening to your concerns and helping you to achieve the end result that you want, it's time to find another plastic surgeon.

I can't see the right breast preop but I would presume there was some asymmetry beforehand. It looks like the breast tissue is lower on the left and the implant higher. You may well have early capsular contracture. You may need a periareola lift on the left to symmetrize or one could use a different implant and alter the capsule and pocket. I doubt an implant exchange and pocket alteration will get the nipples and the breast at the same height. It would be good to see your right breast preop images.

Thank you for the photos and short history.  Unfortunately you will need further surgery to obtain the desired resultDr Corbin

After reviewing your photos you might well have a more pronounced implant capsule on the left leading to distortion and superior displacement and /or both breast implant pockets were not developed evenly at the original surgery. The implants will not at this time even out without some kind of capsule release and/or fold adjustment. It would be recommended that you discuss this frankly with your original surgeon or seek a second opinion if you cannot accept  or function with your current condition.Stuart Kincaid MD, FACS 858 450 4199951 695 9934

I do see that the left implant is high. After 3 years it is unlikely to drop further. My suspicion based on your history is that the implant pocket will need to be lowered and the high side of the pocket closed to prevent the movement up towards the arm pit. Seek a second opinion if your plastic surgeon will not take care of you.