My son has a huge lump on his pelvic area in the right side of his thigh bout the size of a golf ball. what should i do? and it's really hard

Likely a hernia: If baby is otherwise acting normal, i would schedule a visit in the next few days with his doc & see if this is an inguinal hernia. If so it can be fixed while he's healthy in the next few weeks. If he seems in pain, a good soak in a warm bath can often loosen muscles enough for you to push on the lump & help it soften.Then schedule a visit today.