Go and find someone decent who can examine you properly, relate your pain to pathology (or not) and get on and not just treat the symptoms but deal with the underlying cause.
I'd stop stretching as it's pretty obvs it's not doing very much, and on that basis is more likely to be prolonging your symptoms...
You are not out of shape after 4 days hang time.
You're doing far too much and probably have done if for far too long too. Less is more - variety is the spice of life. Let you body recover, get out side and do something different.
Oh, and try this https://www.sixphysio.com/video/back-pain/theworldsgreateststretch
....is that different/changed since you've started to increase your load?
Getting tender or is tender?
Try lots of this...https://www.sixphysio.com/video/back-pain/theworldsgreateststretch
Visit the official Runner's World page
Follow Runner's World on Twitter
Other Natmag-Rodale Sites
Run For Charity
About Runner's World