My Boyfriend Just Turned 38 And Says After Sex It

my boyfriend just turned 38 and says after sex it is really painful as if he was kicked really hard in the groin area,i think he has seen a doctor but isn't telling me so i don't worry about him,he also tells me that it takes a couple of day for him to feel better "down there" after the fact,im trying to figure out what he may not be telling me