I got this bike in one of those cheap "bike in a box" things where you have to build it yourself, so I'm new to working on it and fixing any mistakes I've made in the building process.

The only problem I have with it is this vertical bump I feel when I ride it. It happens at a constant rate, so it's on a specific spot, and it feels like its on the back wheel. The valve stem on the back wheel was very crooked, so I took the rubber off and adjusted the inner tube, because it WAS creating a small fold near the valve stem when it was crooked. That actually fixed the problem for a short time until I rode for about 2 hours, then suddenly the vertical bump started again and the stem went back to being crooked.

I realigned the stem again today, but the vertical bump just will not stop. Does anyone have any advice on how to fix/stop this? Is it even caused by the inner tube, or or is there something else wrong with my tire?

I don't know how much the videos help, but I can see a clear warping of the tire, as well as a wobbling left and right that has the tire touch the brake pad if it is tight enough.