For 1 year now- chronic aches all over body (just like flu aches), recurrent headaches, abdominal pains, always tired, stuffy nose-FBC normal. Causes?

Full exam needed. You need a full medical history and exam. Don't smoke drink or use drugs. I would run a complete blood count, iron studies, metabolic panel, thyroid panel, vitamin B12/folate, CMV, EBV. Just based on the odds you may have iron deficiency anemia since you are a woman of childbearing age, and your stool should be tested for occult blood, blood glucose level checked. If all tests norm *consult me.