Why Do my Breasts Hurt when I Wear a Padded Bra? (photo)

Is still may have some information even three months after breast augmentation which would explain the pain. This should get better with time and with anti-inflammatories. Sub muscular placement is more prone to prolonged convalescence.

Your padded bra may be putting too much  pressure on the breast sensory nerves. Tenderness such as you have experienced is not abnormal after augmentation.  You may wish to try resizing/refitting your bras which may eliminate the problem.  Or your discomfort may wax and wane and ultimately will likely disappear over the course of the next 6-9 months.

You appear to have an excellent result. Normal nerve regeneration after BA often has tender and sensitive spots. Avoid underwires and padded bras until that goes away, but some support is needed.