macbook pro 2024 suddenly has 3 thin vertical lines on right side of display

That is a hardware failure. you will likely need a replacement display assembly, complete.

You can tell its a hardware failure because it shows ONLY on that physical display, not on a screenshot.

additional supporting evidence is that the lines are vertical.

if under one year, it should still be under warranty, unless the glass is shattered. have it inspected and serviced as soon as possible.

Whenever you submit your Mac for service, you sign a paper that you have all the backups you will ever need, and they need not return your files to you. Losing your files is not especially likely in this case, but what is the date of your most recent backup, and by what method?

suzyQ526 wrote:

Thanks. Not what I was hoping to hear but at least it should be covered. This is the 3rd macbook with hardware issues and all of them I hardly had the computer for very long. Very disappointed and frustrating.

Yes extremely disappointing.

Submit your Apple Feedback here: Product Feedback - Apple

In or out of warranty you can get a free over the counter 'Apple Service Diagnostics' test /assessment

Make an appointment for a "hardware issue"

Genius Bar Reservation and Apple Support Options - Apple

Outside the USA

Contact Apple Support - Apple Support

Get your Mac ready for service - Apple Support Get your Mac ready for service - Apple Support

<< Very disappointed and frustrating. >>

The MacBook Pro is a lightweight, portable computer that can run on batteries. Being portable, it can easily be subjected to multi-G forces daily, just by being moved about in a completely ordinary way. This is extremely stressful to electro-mechanical equipment. The display is made of glass, the internals are very likely to die if water is spilled on the keyboard. 

Complex Electro-mechanical devices fail at random, arbitrary, and capricious times. 

Your Mac developed an issue, and barring abusive treatment that cracked the glass, it will likely be repaired FOR FREE.

[In my opinion] You should be thrilled that Apple is very likely to "make it right" at no cost to you.

... But if you don't already have a backup copy of all your files, you need to get started on that right away.

Back up your Mac with Time Machine - Apple Support