i am in 12th week. today suddenly i got pain in breasts around the nipples. and constantly having abdominal pain when i am standing. doctor has advised me bed rest for another 1 month. what could be the reason for breast pain ?

The breasts do get sensitive during the first trimester. But as this is accompanied with abdominal pain as well it appears that your uterus is experiencing contractions. Uterine contractions are also connected with your breasts as both experience discomfort when oxytocin levels are high. Follow your doctor's advice and rest for the prescribed time period.