just relax first of all.it looks more of an anxiety
attack rather than structurel or functional problem.
first of all taking that you must be a student..check your study position.bad position can cause back and neck aches.
and for your constipation
start doing a little exercise(walking)
drink lots of water
take high fibre diet(fruits vegetables)
if still not relieved then try medicines.
and try to keep yourself busy.
i m sure you can tackle it.