Castor oil/labor update

I took 2 tbsp of castor oil at 7:30 pm, no diarrhea or vomiting. Just a whole lot of burping and heart burn. Well the past two hours I've been getting tightening in my abdomen, similar to Braxton hicks except I feel it in my back and lower/middle part of my abdomen and my whole stomach gets hard. Suppose I need to start timing them since it hasn't let up in the past two hours but I was just wandering if contractions feel like tightening in the lower part of abdomen instead of top?! Hoping it's time to get this show on the road!

(Btw my doctor recommended castor oil since I'm 40 weeks, also did my research so I don't want to hear about how dangerous it is, I haven't had any side effects)

Had my baby!!! Perfectly healthy and no health problems!! Castor oil is perfectly fine as long as your body is ready which mine was obviously! Thanks for all the negative comments.