Why are there random people messaging me on Facebook all of a sudden?

[pinkie]

Title says it all really. Two random boys just messaged me randomly this evening, one just says ''Hello '' and the other said ''u back on fb? haha '' I went off of Facebook for a while and didn't use it much so I assume that's what the 2nd one meant. Anyone have any idea why they just randomly messaged me like that? Thanks!
They are my 'Facebook friends' but I still wouldn't call them 'real-life friends' lol
I don't think it's group chat either because when the 1st guy messaged me it was 3 hours before the 2nd guy even though I replied late to the 1st guy. Make sense? xD

[Hammad]

They may be using group chat so don't worry, it also happens to me a few times.

[I ♥ Cats]

If they are listed as your facebook friends then they can message you. If you don't want any further messages from them then you can block them by going to their profile.

[Daniel]

The Only Way to Find Out is to Message them and Ask it Could be Many Different Reasons