What Causes Postpartum Headaches And Neck Stiffness?

I am 4wks postpartum. I had a spinal headache with blood patch at 4 days. The headache came back the next day, but only when sitting. It finally resolved at 2 1/2 weeks. I am still having neck stiffness mainly when I sit prolonged periods. CSpine MRI was negative. Motrin doesn't really help, only get relief from laying or standing. Do you think this is muscle strain from pushing during labor? What should my next step be?