Achy body...even after taking Tylenol

Al
Has anyone felt like their body is overly achy? I'm 4 weeks postpartum and felt good at first but my whole body has felt super achy the past few days...especially my neck, back, and knees. I've also been having pretty bad headaches. I've taken Tylenol but it doesn't really help. Not sure if I should be worried or not.