Suggest Remedy For Pain In The Foot

My son is two years old and he has awaken in the middle of the night about four times now within the past month crying and complaining his foot hurts , i have massaged it and it goes away within 5 minutes. Again this morning he awoke crying that his foot hurt, i noticed several round, red nonraised circles on his foot with heat felt over them, I washed his foot and within a few minutes it went away again. Then again, not too long ago he was crying again, no circles noted but heat was felt over the top and bottom of his foot, i elevated his leg and again it went away, what could this be?