Is it ever possible to travelling through space interstellar without any wormholes such as Stargate???

Yes, it’s absolutely possible to travel in interstellar space – both Voyager probes are doing it right now. The problem is that it will take a really, really long time at any speed that we’re capable of generating, like tens of thousands of years to get to even the nearest stars. If we had something like a fusion drive it might be possible, though in the best case it would be a one way trip that would take most of a lifetime.