my 13 yo boy is slight and short in stature...pre-pubesent and is seeing an endo. he just had an ultrasound today to check his thyroid. Thyroid is fine though, has am 1.2x.4x.9cm hypoechoic structure which has the typical sonographic architecture of thymus (possibly residual thymus tissue). first, what does that mean.. aren't those two organs/glands usually separated? Also, he had "heart pain" yesterday (noting he said it hurt fo 10-15 minutes, feeling pressure no real pain and went away without incident....I put it to frustration with his brother..) should I pay attention to those episodes.. not usual, but now seemingly too often.