Girls, can you tell me something about this? I'm in my first pregnancy…

Girls, can you tell me something about this? I'm in my first pregnancy, 23 weeks. I've been having a pulling sensation in my belly for three days now. It doesn't pull everywhere, but it feels like ligaments or muscles. More on the right side. Could I get sick suddenly and then feel better? Is that normal? Everyone seems to have different experiences, is that normal? All my tests are good, the pregnancy is progressing well. But I'm worried now because of this????