Last week just before I traveled to Ljubljana by bus I started have some major pain in my right hip, but it didn't bother me when I walked or ran. My experience has been that this usually means there is an in balance in my hips. I tried doing an exercise that usually corrects this but it didn't do anything, so it persisted for about a week and then started to get better. Near the end there was also some stiffness in my lower back, but all the time I managed to keep running. So sometimes you just have to see how things go when you have an apparent injury, but still want to run.