what you can try to fix the icon:
post results here, we will take it from there.

Alright. I'm gonna try some of these things. I'll report in a while.

Alright. I installed redshift through the Lubuntu Software Center. I then ran the command dpkg -L redshift. Here are the results:

EDIT: I tried running the commmand but i got the reply

Just learned something important. when i run sudo make install, this is one of the parts of the output that i get

^ that is interesting, however i don't see why redshift would need to run update-icon-cache after installation, because your dpkg output suggests that redshift does not come with its own icon.
i guess it's a generic list of actions that are being performed after installing anything.

next steps:
1) find out what icon theme you are currently using.
2) perform the following command:- my guess is that you will get some results, but none for your current icon theme.
in that case, you have to open the "index.theme" file that belongs to your icon theme (so, e.g. /usr/share/icons/Faenza/index.theme) with superuser privileges, and edit the "Inherits" line, appending the name of the icon theme containing a suitable redshift icon.
Warning: you need to choose the name of the icon theme, and not the name of the containing folder.
They are often the same, but not always.

I actually tried something in the meanwhile. I uninstalled and de-compiled (is that how you say it?) redshift. I opened the Makefile and i changed the following line to .

I then compiled and installed redshift again. I got a message saying that cache generation was successful. But the problem persists!

I tried finding the index.theme file, but to no avail.

I won't insist on any more help, because i think you guys have helped out enough already, so if you are sick of trying to solve this i perfectly understand (i am absolutely desperate myself). However, probably the best thing i would ask any of you out there to try would be to run Lubuntu 14.03, download Redshift's source code, follow the instructions of the HACKING file LINE BY LINE, and then see if the same problem arises.

Thank you all for your persistence, i am very much appreciated.

i'm sorry, but this is not possible.
ok, i understand if you had enough of it, but my instructions must return something.

Sorry, i actually found the file. It was at . I did not, however, find the Inherits line.