I Have Severe Pain, There Is A Large Swollen Area

I have severe pain, there is a large swollen area that starts small on the left side near the top of my butt crack, and goes around to th right side. The left sides spot is small smooth swollen and hard, the right is large swollen hard and lumpy, it's also warm to the touch. It hurts to sit,stand, walk and lay down....it started when I sat down after playing with my 11 month old son.