Had a breast augmentation using areola incision. The scar caves in only when my breast is touched. Is this common?

One of the disadvantages of a periareolar incision, especially if a redo surgery is also performed through the same incision, is that there can be a depression due to scar contraction.  Sometimes this shows up as a shortening of the nipple to bottom of the areola distance, or a downward pointing nipple.  This typically worsens with subsequent surgeries.  There are ways to correct it, but the problem is quite significant and reaches all the way down to the implant.  It isn't confined to just the nipple.
That's why I prefer an under the breast incision in most patients.  This does not require any alteration of the nipple-areolar complex.
There are ways to minimize this issue but I have seen it occur often, even in the very best of hands.

From the photos, there is scar tissue creating the indentation at the underside of the nipple areolar complex. This can be corrected with excision of the scar and release of all of the scar tissue that is pulling the aerola down ("caves in").
Steroid can be injected at the end of surgery to decrease the aggressive scar formation. Also, post-op, the area can be treated with massage and ultrasound to decrease the possibility of further scar and adhesions. 

Hello,
My colleagues want to ensure that choices can be given to potential patients, and frequently present them as equal choices. However, when it comes to incisions, they are not all equal. Periareolar incisions put the patient at a higher risk for capsular contracture, scar tethering (what you have), and breast tissue atrophy.  With time your scar may soften, but it may not. However, any further breast implant surgery should be performed through inframammary incisions, the safest route. Best of luck!