Sm31,
Back pain is usually muscular and other soft tissues in origin. It is possible to have a thoracic compression fracture of the vertebra, from minimal flexion type trauma. This is most commonly seen in women who have significant osteoporosis.
As long as the patient is neurologically intact, compression fractures in the thoracic region are usually just treated symptomatically, with pain medication, short period of rest, and then gradual mobilization and strengthening.
The only way to know if you have sustained a compression fracture is to have the spine x-rayed.
If you are concerned, see your physician. Good luck.