I'm 5 weeks post op under the muscle Breast Augmentation, there is a pain on my right breast. Is this normal?

The pain you're describing is common after surgery, particularly since you're still just 5 weeks out. While it may not be of concern, I recommend you see your surgeon for a physical examination just in case. Best of luck.

The pain you are describing is not uncommon for only being 5 weeks postop. As swelling subsides the discomfort should get better. It is always best to discuss this with your plastic surgeon for an in person examination. 

At 5 weeks postop, you are still early in your recovery period and
are likely to experience occasional mild to moderate pain.  You will continue healing over the next 6-12
months, and as you do so your pain will be less and less.  Sometimes women will have tenderness at the
inframammary incisional scar or slightly below it.  This area may feel firm or may even look like
a raised “guitar string”.  This may be
what you are experiencing 5 weeks into your recovery.  Anti-inflammatory analgesic like Advil or
Naprosyn and massaging of the area can be helpful.  I expect that the pain will go away over
time.  Always follow-up with your plastic
surgeon so that he or she can determine that your recovery continues on track.