Why is my laptop not charging past 31%?

O.K You have asked two questions here which may or may not be related.

Firstly, how old is the battery? If you bought it in 2015 it may just need replacing.

Does the computer work fine with the battery out and just the charger plugged in?

Have you run any battery calibration software? If not here’s some information on that topic:

https://windowsreport.com/calibrate-lapt...

Secondly, for the fan running noisily, have you cleaned the dust out of your laptop. You did not mention if it is also overheating. Here are the disassembly instructions. Work slowly and carefully. If inexperienced first read up on static discharge:

Smontaggio HP Pavilion - 17 g173ca per accedere a RAM e disco rigido

There may be other operating system or software problem causing the fan to spin so loudly.

Let us know how it goes. There may be other instructions required.