I regularly use a Thumper massager to help relax tight muscles and treat muscular problems. The Thumper is a mechanical Massage device rather than a vibrator. The Thumper moves 1/4 inch, 28 times per second, much slower and more forcefully than a vibration type of device. I use the Thumper 'mini pro II'. It is rather expensive, retailing at $190 on Amazon, but the build quality and results justifies the cost. I tend to use the stick for routine Massage and diagnostics, but the thumper for specific problem areas. Most times the Thumper works better for me than manual Massage, though there are deep areas such as the hip flexors where the thumper is impractical.
The instructions that come with the Thumper say that you should not press the thumper against the body, but just use the weight of the Thumper, which is surprisingly heavy. I ignore this advice and push the thumper hard against problem areas. This puts extra strain on the motor, and my Thumper is suffering a little, but has been going in this way for years. If you do push the Thumper against the injury, you may destroy it, so follow my example at your own risk.