I started weights again last week. On Monday I did bench and lat pull downs, as well as intervals on the bike and a short swim. On Tuesday I couldn't lift my arms above my head, and my quads were aching. On Wednesday I went back and did a 40 minute light interval session on the bike, and my legs felt good afterwards.
Yesterday I hit the weights again: bench, wide lat pull downs and added underhand pull downs, in addition to the bike intervals and 500m in the pool. Today I feel great, no pain, no stiffness, no worries.
So yeh, it will hurt for a few days after you first start, then it should subside as you adjust.