Is this Stretch?

No, just a normal growth pattern when flowering is approaching. Branches will stop growing opposite each other and grow in a staggered pattern. Outdoor plants don't really stretch, this is a more noticeable phenomenon in indoor crops, when the light goes from 18 hours to 12 hours, causing the elongation. Plants growing outdoors don't get subjected to this massive disruption, only a gradual 10-15 minutes of lessening light each day. What your plant is doing is completely normal and of no need for concern or worry. It is just an indication that the plant has decided that flowering is getting close and is an age related process. Hope this helps, Organoman.