Painless lump/bubble inside in the penis

Hello! I am 27 and I have a painless lump underneath the skin of my penis, on the right side beneath the head/glans. circumcised. I don't know exactly how long it's been there, a few weeks maybe. Could be related to masturbation? it's not visible but can be feel when I push the crown of penis. Please guide.

What you are describing sounds like Tyson glands although they are usually visable on the surface of the skin in the location you describe. Whatever you have could have been present for some time, or even, from birth, only you had not noticed it.
Unfortunately, the penis can develop lumps and bumps like this, some are surface level and others cannot be seen, this is what you may have, the vast majority are completely harmless.
You mention masturbation: unless you are apply considerable pressure to the penis this is unlikely to cause any issues - so unless you masturbate for 5, 6 or more hours a day, for most days, this will not be an issue.
What is common within some cultural groups is that some men practice natural penile enhancement or enlargement. If this is something you do practice it is possible that you have helped to create, or have irritated something within the body of your penis that has either created, or made this lump become obvious.
As is the case with frequent masturbation, or natural penile enhancement - all you need do is to cease the practice for as long as you possibly can in terms of weeks - then when re-starting, go easy with what you do …

Hello Wee,

Thank you so much for a detailed response. I will definitely consider your advice to cease the practice and avoiding tight underwear as well and drinking more water and taking good care of penis. I will let you know if I see any results. I hope this will go soon.