Should I be worried if found various cysts under my arm pit?

around 18 years ago I found a few cysts under my arm pit, they then amalgamated into a larger cysts which was subsequently removed and the biopsy shown it was benign. The following year the same thing happened under the left armpit. I now have a few of these cysts under each armpit, varied in size, from pea size to larger. They are not painful most times but sometimes I feel pain around the armpit/ area. I was told to check myself for lumps regularly and have done so but lately my left is looking out of its normal shape when I lift my arm up to check. It looks a bit dimpled and uneven. Should I worry and go to the doctors? Doctor told me last time to see him if more cysts appear or if the existing ones enlarge.