Your environment seems to be moldy and unhealthy from what you describe. We suspect your 7 year old paint is bad, probably moldy, and is probably contributing to your respiratory ailments. Latex paint is smelly but not usually a really bad smell.
We strongly suggest that you seal over that paint – pronto – with a KILZ solvent primer and then paint your room again. You must really seal the old paint to block the smell, which I believe is mold. This sealing process is similar to the fire and smoke abatement methods used in houses that had fires and smoke damage.
Imagine the organic growth culture that resulted from keeping your paint can closed, warm and wet inside. Think of what happens to water or moisture (like latex paint) when enclosed in a relatively warm environment with no ventilation for seven years. You have potentially created quite a biological Petri dish of organic culture. Then spread that growing, moldy culture in liquid form all over a massive square foot area where it can out-gas with super ventilation into a living environment for humans. Wow! Drywall compound also gets moldy over time for the same reason and gets discarded after a short time of storage.
Paint as soon as possible and ventilate the rooms well. At least change the air often with open windows until repainted!
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