Hello,
First, my apologies if this issue has already been addressed, I searched and couldn’t find it. 
I upgraded to Lubuntu 20.04 last week, from Lubuntu 18.04 on my Dell Vostro 5481 (08A7) laptop. I’m super happy with it, except for two details. I believe it’s really minor but I can’t fix it myself. The first thing is that, although default sound works fine, if I plug anything in, there’s no sound at all, as though the headphones weren’t working. They are, though, because I’ve used them since on my phone and another computer still on Lubuntu 18.04. I like working with music and my coworkers don’t. 
I have tried using the PulseAudio interface, the headphones are recognized and supposed to be working, except no sound actually comes out. I’ve also had a look at AlsaMixer and it said the same. Here is a screen capture (if you need AlsaMixer, I can put it in a reply):
Has anyone encountered this? Should I find some kind of pilot for random headphones or something?
Thanks in advance! 