6+ yr. old Min.Pin. getting lumps

Question
My MinPin is about 6.4 yrs. old and is getting lumps on his body. One is under his right side ribcage, one is under his front leg, and two more recently appeared on his back. These do not look like they are maintaining size because they appear to be getting bigger.
He has been laying around alot also. He used to jump around alot but seems hesitant to jump 2 ft. up.
Our local Vet. didn't seem too worried about them but he's getting more bumps and the older ones look like they're growing.
What to do?
What to ask Vet. to do?
Samples from the lumps?

Answer
Your vet can always biopsy one or two of these lumps to find out what they are if you are worried.  Often we will see small lipomas that are fatty tumors grow like that.  They are no problem medically unless they grow somewhere that interferes with walking or eliminating.