In your picture your right side looks higher, but this is exagerated by the fact that your right shoulder is held higher than your left shoulder. If you were standing straight with your shoulders level it might still be a little higher. It might help to massage and push the right implant down. You will not be able to raise the left implant without surgery.
6 weeks is too early to consider capsular contracture.
Singulair might help for very early capsular contracture. There is limited data in the literature to support this. Similarly home ultrasound might help a little, and again there is no proof in the literature that this is effective.
6 weeks post-op is really too early in my book for a contracture to develop. But since you have different looking breasts, my question would be what side do you like better and then a plan is formulated depending on what you choose. From your photo, I personally like the higher side (your right on your photo) and would seek options for improving the left side. As for ultrasound, it certainly doesn't hurt but I can't say there is a lot of proof it helps.
I don't believe that a capsular contracture has formed at 6 weeks (or at 2 weeks, when you started your Singulair). I am assuming that you never had impants before? If this recent surgery was to address an existing capsular contracture, then that would be a different discussion. An implant that looks "contracted" at 2 weeks post-op is, in my opinion, simply high in the pocket. If some focused massage doesn't bring the implant down, then it is safe to assume the pocket wasn't dissected adequately, and a reoperation to adjust the pocket may be necessary. This is NOT the same thing as a capsular contracture. I doubt Singulair or ultrasound will help.
I do not have any confidence that ultrasound does a anything to present capsule formation in breast augmentation. Nevertheless it does not hurt to try. The Singulair has proven benefit so stick with that. My Best, Dr C