Ladies if you still have your gall bladders, then it is much more likely to be a gallstone attack or biliary colic than endo on the lungs which is exceedingly rare. Women of the age to be having problems with endo are also the same age to be afflicted with gall stones. Most of us have gall stones. Usually they rattle around and don't cause anyone any problems. Right before a period yout body retains bloat /fluid putting added pressure in your tummy and that is where the gall bladder lives, just under the Liver on the right hand side. So more likely to be having this happen after ovulation when your gynae bits are actively building up ready for a period.
My weight would go up half a stone in the two weeks before a period, just from fluid retention.
However , despite the gallbladder being located to one side the pain is felt right in the middle behind the lower part of the breastbone and radiates out from there.
Attacks can be rare, once or twice a year, all the way through to almost every day for some people. They usually happen after a big meal, which usually means supper as that for most is the main meal of the day. So the pain worsens in the evening and can keep you up for several hours at night till the bunged up gallbladder has leaked out enough bile to calm down.
Many people put this down to indigestion or stomach ulcers, when infact it's just a gall stone blocking the exit from the gall bladder which fills up with bile from the Liver and it can't empty out properly like it is supposed to. It can be very painful and distressing as no painkillers will help, nor will indigestion remedies and ant-acids.
Easy to fix for good, though very long waiting list for ops.
Lap op to have gallbladder removed and that puts an end to such attacks.
You don't need your gall bladder, it's rather obsolete like an appendix.
50 thousand gallstone ops carried out in the UK each year. it is the most common reason for stomach pain causing hospital admissions. Though I'd say it is more of a chest pain than a stomach one.
If you have had your gallbladder removed already then consider other possibilities like endo, but if you still have your gall bladder then with twice as many women to men getting gall stone attacks, and 50% of women having gall stones in their lives, it has to be much more likely than anything else, even heart problems.