how do i make a regular chocolate syrup get solid?

Everything has its own texture when frozen solid. A ball of rubber will never feel the same as a ball of iron, even though they are both in the solid phase. Similarly, if what you are envisioning is the same texture as frozen water, that won't happen with your syrup.

If what you have is a "paste" in the Nutella-like sense, then your syrup is an amorphous solid (this is not the case for pure sugar syrup, but yours probably has a lot of stuff added to it, I wouldn't be surprised if it also has gums). The best you can do is to keep it longer in the freezer (try at least 24 hours) and with some luck, you will get a very hard paste, similar to frozen butter (but not to frozen water). There is no guarantee though, as the mixture you have might happen to stay soft to temperatures lower than what you get in your freezer.

If you want some other texture, you will have to freeze something else.

You'll have to get it pretty cold to get it to freeze. Due to freezing point depression, all of the dissolved sugar in that syrup will give it a freezing point of well below 32F. There are a variety of freezing point calculators available online, most of which probably call for more chemical knowledge of the solution that is available. I can find one source claiming that simple syrup freezes at around 18F though.