It's a brief description, but yes meltdowns come with young kids. Having said that, you can have an impact on their frequency and duration, essentially by being the adult in the room (sorry for the expression, but true) and by thinking long-term. It is true that the surface response (tantrum) may really mean something different: frustration about communication, reaching out for attention, not enough sleep, dietary reaction, or other condition.
The trick, then, is to listen to your child and try to observe the circumstances of the meltdowns: is it often triggered by loud noises? The day after spaghetti dinner? The week after you left him with your parents? When did the tantrums start? Has it always been this way? Was it after he got his last tooth in? Medical opinions can help, but they also will rely heavily on your identification and description of the context of these events.
As to what to do: there are a ton of different approaches out there. No one is "it." But if you try some out, you will find one that 1) works for you and 2) you are comfortable with. For example, many approaches suggest ignoring a tantrum, on the basis that they are often just a means to gain attention. But not only do you have to literally turn your back on your son, (after making sure he's safe) you also may need to endure when the anger turns to sadness or fear, at least in tone. Kind of like getting them to first fall asleep through the night, which might be viewed as the first hurdle. I will say, many of the effective remedies to tantrums are very counter-intuitive, until you understand the root cause of the behavior.
My wife and I follow Love and Logic, as recommended to us by my school-social-worker-Mom. Our 4-year-old son still has tantrums. But when they happen, he is an active participant in dealing with them--getting them to end. It does also depend on us--mostly on us--remaining calm and addressing him through the process, supportive of him but not reacting directly to his emotions. But he usually puts in a good amount of work, too: realizing he is having a fit; getting his breathing under control; looking at the context of the situation, and why having dinner with the family / ending a movie early / going potty before leaving the house / going to bed at bedtime is not a situation that should be so stressful.
The best thing I can say, all technique / theory / hearsay aside, is don't let his behavior drive your behavior. Stay calm, stay alert and open enough to the situation to let yourself observe him and his environment, as you try to figure out what is triggering him. For us, we are still napping our son, because he is a beast when he doesn't get enough sleep. And we feed him much less sugar than I would guess is average, because sugar spikes can also facilitate a nuclear meltdown. By this, I mean fruit is often dessert in addition to a potential component of a meal, and ice cream / cake / cookies are a rare treat, generally when we are away from the home and have some activity at which he can burn the sugar immediately.