Basically, my molar was coming and part of it was covered with my
gums and the other part was trying to come out of my
gums. It hurt because the tooth is growing through your gums. It hurt when I ate anything on that tooth, especially fried chicken. From my experience, it is not serious. We all grow molars. The pain is probably coming from your gums. Take some pain medication.
As for your second molar, it takes a while, but it will break through the gum and your pain will be gone.