Avid runner with no history of side cramps. Now getting them regularly. Lipomas in the area of cramping. Could this be cause?

Lipomas. Lipomas very seldom cause any discomfort. Occasionally if they are situated right under a spot where clothing presses (like a bra) it can be uncomfortable with a dull ache, not a cramp. If you are an enthusiastic runner and this pain is progressing steadily, I would be most suspicious of an overuse injury and would try to reduce the total amount of running (either time or speed) to see if it helps.
Doubtful. If your pain occurs only with running, it is doubtful that the lipomas are the cause. Lipomas can be painful though.