I had slightly tender knees when I started running regularly outdoors last month. It wasn't a stabbing pain - just a tenderness. And it did go away! I ran 5k for a personal best this morning and my knees feel perfectly fine.
I also had tightness in my hips and lower back - that has also eased up.
So, not everything is a matter for a physio. It is usually a matter of your joints and connective tissue getting used to it.
Regarding good shoes: there is no scientific evidence that gait analysis and corrective/orthopaedic footwear prevent injury. In fact, there is a proven correlation between the increased price of running shoes and injury rates.
Now, someone will come along and swear by their speciality shoes. They'll give anecdotes about knee pain until they had gait analysis and bought a particular recommended shoe. Just like you'll hear anecdotes about the miracles performed by chiropractors (also never found to be of any use when subjected to objective study.)
So, I would say that someone who is a newbie to running really only needs to buy comfortable running shoes. You can find them at Decathlon for about £20. I'm sure someone will shriek in horror, but it's perfectly possible to run in shoes from Tesco or Asda. (They probably won't last as long as expensive shoes but they're not actually going to hurt you.) When you reach a level of putting serious weekly miles in, then you can look into paying more money.