Here is my question ( this one may be dumb): Is it a sin to look at women even if they are not naked?
Looking at a woman isn't wrong by itself. "But I say to you that whoever looks at a woman to lust for her has already committed adultery with her in his heart" (Matthew 5:28). In other words when a guy looks at a woman with thoughts of having sex with her or when he strips off her clothes in his imagination, then he is sinning.
I am really having trouble with lust, and I try not to think or do any of it but will Jesus forgive me over and over again if this keeps happening?
Struggling with lust is common for young men. A part of becoming a man is learning to control your body and your mind. The answer to your question is that, yes, Jesus does forgive even repeated sins if the person is trying to do what is right. Jesus does just as he taught us to do: "Take heed to yourselves. If your brother sins against you, rebuke him; and if he repents, forgive him. And if he sins against you seven times in a day, and seven times in a day returns to you, saying, 'I repent,' you shall forgive him" (Luke 17:3-4). The big difference is that he does perfectly what we struggle to do.
"If we say that we have no sin, we deceive ourselves, and the truth is not in us. If we confess our sins, He is faithful and just to forgive us our sins and to cleanse us from all unrighteousness" (I John 1:8-9).Temptation to sin is always going to be there, especially sexual temptations. Keep in mind that God comes first in your life, regardless of what your body wants. In regards to lust, are you staying away from pornography? One of the bad effects of pornography is that increases the lust for sex.
"For this is the will of God, your sanctification: that you should abstain from sexual immorality; that each of you should know how to possess his own vessel in sanctification and honor, not in passion of lust, like the Gentiles who do not know God" (I Thessalonians 4:3-5).
I have been trying very hard not to watch, but I seem to come back to watching it. I feel that I am very weak. Then, sometimes I masturbate. At last I always come to Jesus and ask for forgiveness and say a prayer. Am I doing enough for him to forgive me?
What I would like to do is explore with you a bit why you keep going back to it. I can make guesses based on past discussions with other guys, but I don't want to put ideas in your head. But think about the times you give in and watch porn. What is common about those times? Is it that you are bored, there was no one around, that you had not ejaculated in a while, or something else? I realize that you know that porn is wrong, but do you understand why it is wrong? Do you understand how it works to trap you? I believe if you understand better what is going on, it will be easier for you to have self-control in this matter.