Do you work a desk job or such?
Stretching is a good idea and helps prevent you from pulling things, knotting up when stressed, or in general preventing things like muscle spasms. A weight or quick movement often will provoke these things if you're out of shape.
I used to be pretty bad about posture at work (A lot of desk work). I was active, played soccer and hockey, but didn't take stretching seriously. One night, playing bass, I did something to my neck and had muscle spasms for a good week. Something with the way I was moving, and the weight from the strap being on one shoulder. I quickly acquired the nickname robocop due to my slow head movements. The same thing happened during other activities.
I stretch routinely now and watch my posture at work, and have avoided another injury. Plus I feel more loose and comfortable/relaxed. As you're saying yoga would be a good idea.
Strength is a good idea too but flexibility and stretching should be emphasized. It only takes 15 minutes a day. Add strength in there, another 15-30, and you should be covered
To a speedy recovery.