I experience burning and tightness from my butt cheeks down the sides and calves of both legs after only a few minutes on the elliptical and feel wobbly legged when I stop. I m not winded at all but, the pain is such that I have to stop. I ve only been a month seriously exercising and am feeling frustrated that I can t go for more than 15 minutes without feeling like my legs are going to totally lock up. What could it be and what types of exercise should I be doing to alleviate this and move past this? Thank you!