Yo @Naith and @Alex_Barry , first of all thanks for your concerns.
@Naith I just wanted to know If there were some known issues around SwapWindow, because of that, I didn't put code here in first instance.
Now, maybe you are glad to know I resolved the problem. It wasn't nothing to do with SDL but my OpenGL code. I debugged putting glGetError after every GL call (in order to see If the call generated an error) so I could narrow the hunt until the doomed call. The error was that I was trying to bind a bad-builded VAO, I generated the array with glGenBuffers instead of proper function (glGenVertexArrays).
I apologize for the waste of time, I though my code was good cause OpenGL didn't complain my fault anyway.