Hi Thaidai. It is natural to have some off and on bck pain at your stage of pregnancy
. So no need to be worried about that unless its severe or persistantly bothering.
As the pregnancy progresses, the heart and lungs in the chest cavity are pushed upwards and also there are a lot of changes that take place in the circulation and blood volume. the throbbing thet you feel in your left clavicle
region may be due to the heart and big blood vessels moving upwards, which is normal for you. As you have been operated twice on left clavicle,, there may be some hypersensitivity
due to the scarring there. but nothing seriously seems wrong. Do get your regular checkups and mention this to your obstetrician.
Wish you good luck.