You should see a doctor or sports physiotherapist. I mean shin splints means your bones are not holding up. And if you continue running with this damage unhealed, maybe you will just compound the issues. So i'd say get proper professional advice.
Other than that, i think you are mad to run at such a weight. You can get all the benefit from walking without the damage when you are unfit so its a much safer option.
but even for walking, you need to buy good shoes with plenty of cushioning in the soles.
I'm not too sure how stretching would help but maybe it does.
Shin splints are about the bones. If your bones are weak, you might risk breaking them. So get professional advice. Maybe a bone density test. I say that because i think i've read recently that obesity causes poor calcium absorption and loss of bone density.
http://www.betterhealth.vic.gov.au/b...n_splints?open I recommend reading this entire article.