These are all classic symptoms of inadequate ventilation, with high R-value these days, the humid vapors have no where to go and left untreated cause problems. All you need is to supplement your garage with a little ventilation to remove that problematic air mass and exchange the air, and protect your investement from moisture related issues, like condensation, mold, corrosion. I purchased a garage unit called Wizzvent and it works great, 60 CFM and only uses 19 watts for around $200. Check out their website at www.wizzvent.com
Hope this helps.