How to manage a lopsided gait?

I'm coming back to jogging after a 3 year break after I had a prolapsed disk. I'm in week 5 of a 0-30 min beginners programme at the mo and am having some shin pain in my left leg, + my left arch aches a bit. Before I started the walk/run I went to get a new pair of trainers fitted. I was told that I'm over-pronating in my left foot but not my right, so on the shop assistant's recommendation I bought a neutral pair of shoes. However, I have been assuming that the two problems are linked. Could I wear an orthotic in one shoe and not the other, or would that be completely crazy? I've been so happy with progress to date and now feel completely gutted that I may have to ease back. I'm also very overweight at the moment so I worry that this is putting more stress on some weedy muscles! Any suggestions would be massively appreciated.

I also over-pronate just on one foot which gives me lots of injury problems in my left leg. I've never really cracked it but the theoretical answer is differently shaped orthotics in left and right shoe. Best to see a podiatrist to assess you properly as they may recommend both feet need one rather than just the left. I have tried them several times but never made much progress.

I don't get the bit about neutral shoes on their own - neutral shoes combined with orthotics yes. I tend to just wear shoes for over pronators and the 'good' foot/leg doesn't seem to suffer for it.

Make sure you do your runs in both directions, it sounds silly but it's not a mickey take. If you run a particular route the road or pavement camber present will have an effect, and when I had a right sided injury I alternated my runs make both sides work evenly