Three tools, three jobs. Foam roller — big areas: quads, upper back, lats. Lacrosse ball — one specific spot that needs attention. Massage gun — convenience and speed anywhere in between.
All three do roughly the same honest thing: temporarily reduce that tight, stiff feeling and help you move into your warm-up or wind-down. Muscle, not bone. Never the spine, neck, or anything injured or swollen. Comfortable pressure — pain isn't progress here.