If you are overweight, on the pill and have a family history of heart disease, esp at a young age, you are at risk of heart failure, heart disease (as in risk of heart attack) and also PE - blood clot. Sorry, that sounds awfully brutal, and I really don't want to frighten you unnecessarily, because I know that gall bladder pain can be horrendous. However, NOTHING can be diagnosed over the internet or phone, and if you were my relative I would take you to A&E.
I also know that A&E can mean a long wait, but I still think better safe than sorry.
The phlegmy feeling could be due to congestion in the lungs due to any of the things I have mentioned.
I am sorry if anyone thinks I am being too graphic, but I can't see you, so am urging you check it out with someone who can.