If there was no pain before you started running, you're probably overdoing it. A mile and a half really isn't much, and your cardio ability might be there, but your soft/connective-tissue ability might not be there. That stuff takes a long time to recover and strengthen.
Also, if you've never run before, your musculature is probably wacko and imbalanced. This is also something that will not develop overnight. If it's bad, it can also really jack up your form.
Form, by the way, is another thing you should investigate. If you heal-strike when you run, you'll be in for some serious trouble. Think about scraping dog poop off your shoe when you run, or pulling the heal of your foot up to your butt. (You don't want to look like you're prancing like a show horse, but just be cognizant of the muscles in the back of your thigh.) Also think about spending as little time on the ground as possible -- meaning get your foot up right away. These cues should help with form basics. If you ask me, it's better to run fast for short intervals with good form than run slow for long intervals with bad form.
That said, yes, I know, it really sucks. When you start running, you'll definitely find your aches and pains will slow you down more than your cardio-level will. Nobody wants to take it slow when they're doing something they enjoy. But it's important to get a good base so you can keep it up for a long time!
So, try following a training schedule like Couch-to-5k that will help you gradually on-ramp. It will give your connective tissues a chance to progress at a healthy rate. If you're really chomping at the bit to get in more cardio during off-days, I don't see any reason not to add low-impact activities like biking, paddle-boarding, or rowing to the mix, so long as it doesn't exacerbate your pain.
Regarding the inflammation: we aren't allowed to play doctor here so it's not our place to make medical recommendations. But lord knows what kind of issues you could be having there. Your buddy is right, ease-up and reset. Start a logical training progression and it'll probably go away, but definitely visit a doc otherwise.