There are multiple speculations on the root cause of this problem. It is generally agreed upon that the pain is resulting from muscle or ligament spasms in the abdominal region. This means that the...
This is because you start developing "stress fracture" to your bone. Take 3 to 4 weeks rest for relief. Always consult your doctor. It will recur if you run on a hard surface for long.
Hmmmm... Depends on exactly where it is...
If it's along the posterior [back] brim of the pelvis, most likely it is musculoskeletal.
If it's up around the bottom ribs, and you've noted blood...