5 year old Son lump behind ear

Hello everyone, my Son has recently had chicken pox in January and since then I have noticed a hard lump behind his right ear. I always put this down to swollen lymph node with the body fighting the chicken pox etc. Today I noticed a hard lump on his shin maybe about a pea size. He says it doesn't hurt. I'm concerned because there are now two lumps. He does has bruises on his legs from playing with his brothers etc and I'm wondering could the lump be from injury. So terribly worried as cannot contact surgery until Monday. Rang out of hours and GP said they were unlikely to be connected. He is otherwise well x