I should have added a disclaimer, but was hoping my involvement in this thread would act as one. Remember though, if I do an 8/9 minute pace, you can forget about anything over 1-2 miles ( or maybe 3 , we will see). Long story short is that the real runners on this thread would crush me, unless it was over short terrains ( think of gimli from lord of the rings). Listen to them before listening to me
Maybe just trying a 5k is a bad idea if you are in sub optimal condition. My laymen advice would be to work on suitable intervals. Get comfortable with 1200 meters, than 1600 meters. Continue to improve your times on both. Feel strong. As you finish strong, add more distance. My progression was 1 mile, to 1-2 miles ( break in between), than tried a 5k. This over the span of several years, all of which was inconsistent.
what I would tell you- ignore the no pain, no gain matra.
Overall, agreed here. There are different types of pain. Some are workable, some are very bad. You run the risk of serious injuries if you don’t know yourself and work through bad pain. When in doubt, don’t . its not worth permanent injuries. One time I was pulling heavy deadlifts, and I felt my goin tweak. Having not warmed up, I knew I just pulled my groin ( very common injury in ice hockey). I was partially injured for 8 months and it affected my performance.