Greetings, sorry about the pain. It is quite normal to have this pain, perhaps they could have overdone it. Any bruise or strain on sternum will take a month to go. So not to worry, ice it twice a day. Lying is the worst culprit as you turn your sternum gets disturbed and body weight is on it so it is further strained. Lie flat on your back and try to avoid turning sides.
Next Steps
see a physio with knowledge about trigger therapy so that sternum gets relaxed and pain subsides to 40% right away.
Health Tips
if any doubts do let me know