"Apart from the human hands, there are a number of items that can be used to give a massage - from fancy electronic devices, to items you can find around your house."
While hands attached to a human are the best way to receive a massage (since those hands should be attached to someone with a brain that can analyze, tell what the massage needs to do, and make adjustments accordingly), in a pinch, there are other options. There are tons of options for electronic or mechanical massage devices out there - ranging from handheld items, to mats that you lean against, to chairs that you sit in. (I highly do not recommend google-ing "electronic massage devices" because you will likely get a bunch of stuff you don't want to see and don't want in your search history.) These items can be useful, but often they only do one thing - vibrate, buzz, or roll - and even if they do a combination of all 3, it can be difficult to get it exactly right as far as where the work needs to be done, how deep or light it needs to be to be effective, and if the issue releases or lets up before your nerves actually register that a change has happened. Nonetheless, these items can be good for self-care in between massage appointments or general everyday use to reduce stress.
If you don't want to splurge on expensive items which may or may not work properly, you can probably find items in your house that do pretty much the same thing. A tennis ball is probably my favorite tool to provide quick massage relief to feet, wrists, back, and even neck. (2 tennis balls in a big sock, tie the end shut = best massage tool for the neck and where it attaches to the skull that I have ever found.) no tennis balls around? I have used a number of my kids' bouncy balls or other toys - and yes, even those obnoxious legos can provide a decent massage if used properly and not found unexpectedly in bare feet. No toys? A can of soup rolled along the forearm and wrist can help with carpal tunnel pain, or used on the thigh can clear out lactic acid buildup in sore quads from that first-bike-ride-of-the season. Soup can too small? Try a rolling pin. If your pain is being caused by inflammation, toss a single use plastic water bottle in the freezer and roll your foot on it to relieve plantar fasciitis - the ice calms the inflammation, and the ridges in the water bottle provide a nice massage.
There are many more items you can probably find around the house if you just get creative. Of course, mechanical or in the cabinet, tools can provide quick relief for acute problems, or can be good for short-term or every day issues, but they are no substitute for a real massage. A real Massage Therapist can identify what the actual problem is - and it may not be where it actually hurts, which you may not realize when you have pain - you just want the spot that hurts to stop hurting. Real hands can also detect what the problem is, what specific technique needs to be done to best address the issue, and make sure you don't get hurt or bruised int eh process of getting the issue resolved. Which is why tools are great to have on -hand for quick fixes, but a massage appointment should also be a regular part of your self-care routine.