Issue with my laptop keyboard

My HP Pavilion laptop keyboard has been acting weird for around a month now. It'll act as if I'm holding down a certain key when I'm not. E.g. it'll sometimes start typing in caps and open things that i click in a new window, as if i was holding down the shift key. Sometimes it's ctrl, alt and alt gr. To fix it temporarily i just double press whichever key it is or else lock my laptop using start+L.

I've noticed that the arrow keys are the triggers. When i press the up or down arrows a few times it triggers the shift key, left triggers alt and right triggers alt gr. Also when i use shift/ctrl the it'll happen, as if i had on sticky keys which i don't.

i've tried resetting my computer, a complete recovery but neither worked. The HP Support forum suggested ordering a set of recovery media but it'll cost £40 so i wanted to get another opinion first

Does anyone have any ideas of how to fix it? Could it be a problem with the wires or ribbon cable or should i just try the recovery media?

Sorry for the long and messy question