You really need to get the codes read. The CEL can mean one or several of literally thousands of things. The OBD readers are dirt cheap, or you can get a free reading at many auto parts places. With that info, it should be possible to get actual meaningful advice.
Ding ding ding… we have a winner. ;-) Seriously, you're way (!!!) past due on valve adjustment, and it's also VERY likely that the now horribly out-of-adjustment valves are causing both your misfires and your P0172 problem too. And hey, even if they aren't, you really (!!!) need to get those valves adjusted post haste before they are damaged (or possibly "damaged more"). Then reset the error codes and see what happens (I'm guessing you will have fixed the problem).
I'd respectfully disagree with that, 2002Acura. I know the valves on my 2004 with 170,000 miles had virtually no clearance, and if you continue that trend, you end up with "negative clearance" where the valves are never quite "released" by the cam / rocker arms. Plus, there was a noticeable improvement in performance and gas mileage when I did the adjustment, so I considered it well worth the cost (which in my case was a couple hours hunched over the radiator). I should add that there are a LOT of people who have fixed misfire issues by only adjusting the valves (indicating that it really does do something beneficial, of course).
There's really no single difficult step in the process. If you're comfortable with "fiddly mechanical stuff", you shouldn't have a problem. It takes a little bit of feel to get the hang of gapping valves with a feeler gauge, but it's not difficult. A time-saver for me was using my phone's camera (in video mode with the "flash" on) to locate the cylinder markings through the peep holes. The angle is tough to do with "just eyeballs".
The best option is to ask around and see if you have a buddy who's done this kind of thing before (most of 'em will have gray hair). ;-)