Yoga is a great idea for many — probably even most — people, and has certainly been good for me. Another comment suggested the possibility of Ehlers-Danlos Synd

Yoga is a great idea for many — probably even most — people, and has certainly been good for me. Another comment suggested the possibility of Ehlers-Danlos Syndrome (among other things, a connective tissue disorder), however, for which yoga can be somewhat contraindicated. I'd want to that rule out before beginning a yoga practice beyond Yin or restorative. A friend with EDS practiced and taught Ashtanga for years before her diagnosis. The ways the syndrome affects the joints meant that she was able to perform asanas from the later series within a couple years of beginning her practice. Since she was doing stuff she was only capable of doing because of her condition, however, and not stuff she'd trained up to, she ended up doing significant damage to her joints; she's at the point now where her shoulders often dislocate just from carrying too many full grocery bags up the stairs.