You should be fine if it's just DOMS. If it is a niggle, not so much.
On a different note, I'd consider having some kind of goal. Ideally a long term goal with medium term goals along the way. There's nothing wrong with not having a rigidly set program as such but knowing where you want to go is a pretty big part of getting there.
The follow on from that is knowing what will get you there best. So, you don't need a program, although IMO 99.9% or people do better with one, even if it is super flexible.
Just for example, if your goal is a 700 lbs squat and you know your squat goes up when you squat twice a week adding weight every two weeks and do a bunch of GHR then squatting three times a week adding weight every week and doing a bunch of lunges won't necessarily do you that much good.
So, especially if you're busy, I'd highly recommend following a good program that fits your goals (I can virtually guarantee there's one that'll suit you on this site) otherwise you're at a fairly high risk of spinning your weeks and wasting valuable time.