Backache

Hurt my back and can't move much nor sit long. The cause as far as I can remember is that I lifted a small box of a hanging scroll (forged painting of 応挙) from floor to a shelf in a 140cm high storage room --- not enough hight for a grownup to stand up straight. I had to bend over and the moment I lifted it up something (very faint, so faint that I didn't care) went wrong with my lower back. It was not bad throughout that day. But the next day, I found it hard to get myself up. 3 days have passed and still I have a difficulty in walking. Usually it turns for the better by this time but it shows no sign of it yet. That's what aging is...