I am 3 weeks post op with 425 cc implants and breasts are hard and a little painful, is this normal?

Thank you for sharing your question and congratulations on your breast augmentation procedure.  Assuming your breast has not materially changed in appearance or sensation, tissue swelling is likely causing the firmness to your breast.  It often takes patients a few months to have their implants settle and soften and coincides with swelling resolution which maintains your implants flattened and high against your chest.  Hang in there and allow your results more time to mature.  Let your surgeon know of your symptoms as they can provide you with reassurance.

Hi.  It's best to return to your operating surgeon for an in-person evaluation of your hardness.  There are several possibilities.  Do you have textured implants?  Is one breast more swollen or bruised?  Is one sitting much higher than the other?  Do the implants still move when you massage them? This sort of question is difficult to answer with more details..

congratulations on your breast augmentation. Review are still early in recovery and the breast implants likely have not softened as much as a well over the next 6-8 weeks.  However it is best that she is seeing your plastic surgeon for an examination  to make sure that you are progressing normally  and not rely on intermittent advice from physicians who have not examined you.