I graduated from University around 5 years ago with degree in Mechanical Engineering. Ever since I've been working in an engineering position for a supplier within the automotive industry. When I started the compensation seemed fair for a new graduate (~$63k/year + benefits). In my time there I've made significant contributions and some huge improvements in my department. The most significant being developing a software application to improve the way we process test data. This massively reduced the time and effort needed to process and summarize the data as well as made it possible to view and present data in ways that weren't possible before with the outdated application in use when I started.
Meanwhile I have a coworker who started earlier in the same year (also right out of the same University, same degree, and working in the same department). I learned early on from him that his starting salary was slightly higher than mine (<$1k more per year). Now this coworker isn't exactly a high performer, he makes frequent mistakes, is slow to accomplish tasks, etc. He is leaving for a new job paying significantly more ~20k more per year (good for him). Since he is leaving I asked him how much he makes at our current company and he still makes more than I do despite my significant contributions and the "promotion" I earned (he hasn't been "promoted"). The difference now is slightly more than the original difference in salaries but still less than $1k/year difference (I now make ~$75k/year + benefits now).
I was furious to learn that even after I've been “promoted” he makes more than I do. To be clear I'm not upset with this coworker at all but rather with management and/or corporate pay practices that impede management from properly rewarding employees with increased compensation. I've been given bonuses amounting to less than $1,000 for the software applications I've made so I guess it hasn't been entirely unappreciated but certainly underappreciated.
I'm now motivated to start actively looking for a new job elsewhere. I'm looking for commiseration and/or advice, particularly job search advice.
tl;dr Average coworker still makes more than I do despite starting in the same position, in the same year, and at roughly the same salary. Meanwhile I've made huge improvements for the department and been “promoted”.