<human>: Give me the gist of the text in a nutshell

I've been at my job for almost five years. I started out as an associate and was promoted several months ago. This came with a pay raise of about 6k plus slightly bigger bonus. 

My co-worker, who has the same job and was hired the same time as I was, is making two or three grand more than I am. He was promoted before I was because he had an internship with the company over a couple summers before being hired as an associate. But now that we're at the same level and in the same department, we should technically be making the same amount of money. My company is pretty strict about pay increases and only seems to do it alongside promotions and cost of living.

I experience a lot of stress at this job and I feel that, co-worker's salary aside, I am underpaid. Most people in my job with my level of experience are easily making 10-15k more depending on their location (via Glassdoor inspection). How do I go about asking for a raise when I just got promoted less than a year ago? Or should I wait longer? Do I bring up my co-worker's salary or do I say *the reasons why* I feel that I deserve it? I work just as hard if not harder than he does, but we do not report to the same people. 

I have thought about switching jobs, but my current situation does not allow me to just yet. 

I really appreciate your feedback.
<bot>: Co-worker with same job in same department has a better salary. I'd like more compensation but I don't know what to do about it.