Should I ask my dr?

Catalina
So today i noticed a hard lump when i feel the right side of my utirus* im 13w pregnant and it hurts mostly on the right side and it hurt on that side when they looked for the babies heartbeat yesterday with the fetal dopler thing and they pushed on that side. So my question is, is that the baby/placenta ? Or could it be something different should i say something to my dr ??