Sound worked fine through speakers using 19.10 Lubuntu for a few days and suddenly stopped working.
I'd upgraded from 18.04 through to 19.10 if that is relevant, which I've read similar questions about sound lost following that upgrade.
My speakers and Youtube (for example...) are both not muted and there is zero sound. I unplugged the speakers and again zero sound.
How do I restore sound to my system?
Update: got this message when following terminal suggestion:
Command 'pavucontrol' not found, but can be installed with:
sudo apt install pavucontrol
I followed the terminal install prompt for pavucontrol even though from the bottom left of my screen in the menu it says I have Pulse Audio (same program, correct?) and it gives me the lock error I received at the end of my upgrade to 19.10 also:
E: Could not get lock /var/lib/dpkg/lock. It is held by process 29189 (dpkg) - open (11: Resource temporarily unavailable) N: Be aware that removing the lock file is not a solution and may break your system. E: Unable to lock the administration directory (/var/lib/dpkg/), is another process using it?