Shin splints or stress fracture?

I've been suffering with pain in my right leg for a while now, its sometimes a sharp pain down the side of my shin (hence why i've put it down to shin splints) but more recently its spread round the back of my leg, its like sharp shooting pains around my whole lower leg that make it feel like my leg could give way at any moment. It usually hurts during other exercises as well such as power walking, coming down the stairs etc but nowhere near as bad. I can also pin point the pain afterwards if I press down on the muscles a long side my shin. No stretch seems to 'get' at it either. Nothing I seem to do has been helping, I've spent £100 on running shoes fitted professionally with gait analysis, had up to 4 months of rest and taken it slowly, but it doesn't seem to be getting any better.

Have been running on and off for nearly a year now (had 4 months off travelling about 5 months ago and before then I didnt take it as seriously as I do now) and i'm now at the point where i can run 5/10k at a time and have entered a couple of races, still find it hard but considering I couldnt run for more than 5 minutes last year I think i've come a long pretty far. I usually run about 3 times a week and use the cross trainer etc on the days that I don't run so even other strengthing exercises are not working.

The only thing thats stopping me now is this pain in my leg. I have to take ibruporofen before every run which I don't like doing and usually have to ice on bad days. Seems as this is only happening in one leg do you think this could be a stress fracture? I thought having 4 months off would have sorted the problem but even though I came back into running very slowly it came back straight away. The pain is usually bad when I start out my run, it eases off during then comes back again when I stop.

I went on a run this morning and hobbled back in tears, the pain felt completely different this time though, more like very severe pins and needles around my whole lower leg with shooting pains meaning I could barely even walk. It was even too painful to stretch the leg afterwards. Now I can only feel pain down my shin again.

Sorry for the essay, does anybody have any idea what this could be? I'm worried i'm going to have to either give up running all together or just learn to live with this problem which will hinder me forever as rest just doesnt seem to have worked!