What would be the best procedure to fix my asymmetrical breasts?

Far more important than the technique is the skill and experience of your plastic surgeon. Choose your surgeon rather than the technique and let them explain why one technique may be better than another. See the below link on some suggestions on finding the most qualified Plastic Surgeon for a  Breast Augmentation.

HI there, Thank you for your question. You could choose to have a breast lift on the right side to correct some asymmetry. Your scar will go around the areola and down the breast, you may require a small incision in the breast fold. It is best to see a plastic surgeon and be assessed in person. Best, realdrsix

very easy to lift the breast and make the areola smaller. probably take about an hour. go get a consult.  on a personal note , doubt the guys you have been intimate with have perfect bodies either so relax

There's no reason you should be dealing with this. There's a relatively straightforward fix. A small reduction and lift of the right breast. They will never be identical, especially because one will have a scar (lollipop or short anchor pattern) but at least they will able to be very close to a match. Definitely go on a consult or even two, and come up with a gameplan with a doc you trust.

     It is possible to correct the differences between your breasts, making the right one less droopy and also making the areola smaller to match the left.  This would involve a breast lift (mastopexy)  with a scar around the areola and vertically downward from the areola (the "lollipop or tennis racket" shaped incision).  Discuss with your board certified plastic surgeon and good luck.