4.5" (11 cm) is just 1.2cm short of the global average, you can to do some PE, but i dont know what else to tell you.
But injustice is pretty subjective, i know some short skinny dudes (150 cm) with big penises (20cm+) that will gladly exchange 5 cm of dick for 30 cm (a foot) of height, they think being taller will solve most of their problems, that is unfair that some guys are born taller and get more respect.
But sometimes is really all in your head, i am tall like 192. cm with i think is an above average penis size and i used to think that i was never good enough that i have to compensate, there is always a problem, no muscular enough to get respected or not white enough to get respected or i even learned to dance even if i didn't enjoy it too much, because dancing is what get you women.
And even things that were not a problem at the moment become a problem in the right conditions, i once remember when this short very skinny feminine looking guy pull out his penis and it looked gigantic in his small frame and even though we where the same size at the time 21+ cm i couldn't stop myself from feeling envy towards the guy. Now that i am a bit older i just don't give a shit about pretty much anything in life. Sometime is just you damn head, man.