Study a baby. She has no limits. Her mind is a lush landscape of potential and possibility. Properly cultivated, it will lead her to greatness. Filled with negativity, it will lead her to mediocrity, at best.
No experience, whether it is public speaking or asking your boss for a raise or swimming in a sunsoaked lake or walking along the beach on a moonlit night, is inherently painful or pleasant. It is your thinking that makes it so.