Dear moms, I have a problem for four days now my baby is crying terrib…

Dear moms, I have a problem for four days now my baby is crying terribly and arching her back specifically when I put her down for naps and nighttime sleep, even while breastfeeding! There's enough milk in my breast, it starts crying as soon as you pick her up and she falls asleep after 5-7 minutes of crying, then takes the breast and falls asleep. During wakefulness everything is normal, she laughs and giggles! I'm about to go crazy from these fits. What's the reason? Has anyone experienced this? We will be 4 months old on August 15th. Could it be regression in sleep?