re: Terrible rhomboid knot/pain

Theracane is good. Lacrosse ball will be just as effective. If you have a massage gun there are wall/door mounts that you can use that are relatively inexpensive. I just use my bike stand.

Middle Traps/Rhomboids are scapular retractors, so stretching them would look something like the bottom portion of an inverted row. I also like to cross my arms when stretching those muscles out.