I squatted for the first time in a month today. I keep the hard arch in my back to keep my lumbar spine neutral. Now, after my workout, I'm feeling really tight in my mid-back. I can't really tell this early if I'm going to get sore or not. Could the tightness be a sign of bad form? Maybe too much arch in my spine? Or does my body just have to get use to squatting again?