I'm really worried after getting an ultrasound report which says my uterus is bulky and there's a hypoechoicovoid solid mass in the posterior uterine wall that's quite large at 42x31mm. There's also another similar mass, though smaller, about 16x15mm, in the anterior uterine wall. Could you explain what this means, and should I be concerned about these masses? What might this indicate about my health?