Welcome on practo. I am suspecting for Erectile Dysfunction. I would need more information regarding the problem. Masturbation habit, pornography use, lifestyle associated risk, and misconception regarding sex, etc are some important ares to explore. A detailed conversation is needed.
Next Steps
A consultation with a Sexologist is strongly advised. Also, you can ask a direct query here on practo or visit one nearby you.
Health Tips
Do not worry. It is treatable.