I have skin rashes, headaches, lethargy, neck pain & shoulder aches. ongoing now for 2 years, not getting any answers from my doctors or specialists! what could it be?

Probably nothing bad: If they've been working things up for 2 yrs & not found anything terrible, then it's very very unlikely to be anything (assuming your doctors aren't completely incompetent). Stress & depression are always a possibility but you're best judge of that. Treat symptomatically & try not to worry about it.

Food allergies. : You need to have igg food allergies tested for wheat/gluten/casein/egg and many of the other common causes to rule it in or out. Ige or skin testing is not complete.

Multifactorial: Complex chronic symptoms like this are a multifactorial consequence of hormonal, immune system and nervous system dysfunction resulting from genetic predispositions and dietary and environmental insults. These factors impair the patient's ability to produce energy and they end up chronically fatigued, with abnormal immune systems. Poor diet, suboptimal sleep, food and other allergies contribute.