I am 20 and feel like having issues with erection. i might have low t as it came out to be 240 when tested at 11am.is there a cure for this at my age?

Be patient: Don't take testosterone. You are young. Take good care of yourself, eat healthy, exercise, and see how you feel. Recheck the level if you do not feel improved, but never treat hormone problems based on only one reading. Testosterone supplements will make you sterile, and are rarely the right answer for a 21 year old man.

First that testing: Time is not ideal. If a true evaluation for hypogonadism(low T) is going to be undertaken, it should be an AM test in the 8-10AM range. Also the test should be fasting as food including glucose can lower testosterone measurements. Also, the diagnosis and subsequent treatment shouldn't be made on one isolated value. This is the type of test that should be repeated to confirm any hormonal deficit