What causes a burning and painful sensation on the inside of the penis during masturbation?

Hi doctor,

I am 19 years old. I have been masturbating for several years. Sometimes, it was off, but often done. My penis size is fine according to Asian country. But recently, in the past few days, I have been masturbating three times a day. Last two days ago, during masturbation and ejaculation, the inside of my penis felt burning and painful. Then, the semen came out naturally. There was no bleeding or anything. But since that day, the penis feels painful, and there is light burning. But it is not always like this. The time of urination is going well, but it is feeling that it takes a little more force than before. My penis is still arousing and getting hard normally, but a little less than before. It should be noted that since that day, I have not masturbated, and I am already drinking plenty of water. I am taking black cumin and honey every day. Now, is this a serious problem? Or will it be a problem to take the baby in the future?