Go and see a physio! You can get a referral on the NHS from your doctor, I get in to see mine that way within 3 days :-). Yours might be a bit slower so you might need to go private.
I have allsorts of sporting ailments being an old giffer who started sport in my mid forties.
Currently having a knee issue which is caused by my hip, and got some exercises to strengthen and balance up my muscles.
Seeing a great difference within 2 weeks, and I have been running and cycling during that period.
On the subject of shoes – I got some running shoes from a proper shop, after they did a gait analysis. Those shoes always give me shin splints, so that was £70 wasted!
I went in to a another running shop a couple of months later and bought some shoes that felt like they fitted perfectly from their sale rack, no gait analysis, but a bit of fit and feel advice from the shop owner, and hey presto no more shin splints! I do all distances up to half mara and lots of triathlons and duathlons as well as 3 runs a week.
I think fit and feel is more important IMHO.