Can years of watching porn cause poor erections and hard to maintain erections in a 20 year old? if yes, what can i do to recover?

No!: Watch all the porn you want as long as it doesn't interfere w/relationships, family, school, work, etc b/c it won't cause erectile dysfunction. If you're worried, stop watching. Instead, focus on your health. Eat right & exercise regularly. Don't smoke. Don't drink to excess. Don't take meds that aren't prescribed for you. Review prescription meds w/your doc especially for ED side effects.