Intercostal Pain?

[Girth]

I've been between morning and evening weight training sessions, due to personal obligations. I recently went back to morning again. Prior experience has taught me that my back seems to be succeptible to injury during these morning weight sessions. I'm thinking it might be a hydration issue, as I'm always sure to ride the bike for 15-20 min. prior to my workout.

A couple days ago, I did my first set of 5 on the squat. On the 2nd rep, I felt a sharp pain in my mid back, almost like a spasm. This pain has since been with me, albeit to a much smaller degree. It is exacerbated with deep breathing. Thus I'm assuming it's an intercostal strain. Am I correct? Just rest it I'm assuming?

I know morning vs. evening workouts have been bantered about, and there is evidence that morning is more catabolic than evening. There is also the hydration issue with regard to morning workouts. But, as I'm not getting paid to train, I have to do what I have to do. Any other pre-morning workout tips beyond a quart of water, 20 mins. of cardio, small protein/carb drink, that could prevent the above from happening again?