I have been looking for an answer on this everywhere but can't seem to find it. Why does every prayer have different number of rakats, for example Fajr only 2, Zuhr/Assr 4, Maghrib 3, Isha 4. What are the meanings behind these? If someone could explain this I would be grateful.
There is a reason you can't find an answer , The number of rakats were related by prophet Mohammed (PBUH) without an attached reason to why exactly they are like that .
Thus it is safe to say that these are matters of Ghayb (The unknown) and subsequently nobody can claim to know anything about them .
It's similar to questions like , what are the broken letters in the beginning of some Surahs in the Quran , or why do we pray five times a day while ,say , the Jews pray three ?
Thing is , we don't know , This is what has been related to us by Prophet Mohammed and he didnot discuss the reasons , so this is where our faith in Allah's message interferes , we donot question the reason behind it as long as the prophet didn't impart it to us .
prayers are gifted Muhammad (PBUH) from ALLAH at the time of Maeraj. we are muslims and according to this we follow Muhammad(PBUH). So, your question about prayers is meaningless.