Backing up 2 apple devices to the same laptop?

Can you back up an iphone and an ipod to the same computer but have different music on each of them?
currently I have my ipod backed up to the laptop but need to back up my phone - if I plug my phone in will it mess it up and lose everything?

Why does iPhone keep asking for iCloud apple ID password?

I don't use iCloud and I never have, but the other day my friend added me to a reminders list using iCloud and I added myself but I don't use iCloud so I just signed in with my Apple ID and it worked, don't ask me why. I've turned off iCloud now, but still, every few minutes a bubble will pop up saying to give my Apple ID password for iCloud so I type it in but it says its incorrect.
I tried to reset my password but I don't use the email that I signed up with anymore so I can't email myself a link.
I'm on iOS 9 with an iPhone 4S btw. I don't know if that will help but:/
also, this is a really big problem because I can't even download off the App Store anymore since it says my password is wrong.

IPhone 5C Only Vibrates, No Sound?

So here are the details, I have a blue iPhone 5C and for some reason when anyone calls there's no sound it only vibrates, and whenever I play music it doesn't make a single sound whatsoever, but when I have headphones in, I have music. I know the speaker must work because when I'm talking to someone after answering I can hear their voice and for some reason on Skype when I receive a Skype call I'm able to hear that, my phone isn't on do not disturb, and I've tried tapping the default ringtones but the default ringtones don't play a noise, they just vibrate the actual tune? So IIm really confused, please help.