Uy, at 36 weeks na kayo, kailangan talaga kayong makita ng doctor agad para ma-check properly, hindi kami dapat mag-assume sa ganitong stage ng pregnancy, ha. Pwede pang maraming reasons, pero ang OB lang ang makakasabi ng tama. Some of my mum friends nag-experience din ng back pain at cramps towards the end, pero importante talaga na i-report ninyo lahat sa doctor, lalo na kung may ibang symptoms. Better safe than sorry, especially this close to delivery na! Keep me posted, at sana everything's okay na with you.