The knee pain is most likely a muscle imbalance issue. A good core stability strengthening regime may go some way to address this through stretching and exercise, however a good sports physio would be best to advise.
As you’re mostly running off-road and its slippy, any gait analysis (if you believe in it anyway) goes straight out the window.
Get to a decent running shoe and get some shoes that fit well (are comfy) and thats the main thing. If its getting muddy you can’t go wrong with Inov-8 Mudclaws (go for the 300s) although watch out for their wide / narrow fits (or whatever they call them now) as sometimes only certain models are available in them.
Other makes / models exist but these are a go to winter / all-round shoe for 1000s of runners.