I'm 14wks, also experiencing pain on my left side (upper & lower quadrant). OB said it can be because of the bloating and constipation (the latter usually pag lower left abdomen). Pwede rin naman daw because lagi na tayo side-lying kung mahiga, especially if naka bedrest.
Observe na lang po mommy yung pains mo. Basta po hindi sustained, it should be okay. Pero if iba na ang pakiramdam mo, contact your OB right away. 🙂