I have recently been having the same issues with my DD (16 months), she was passing very hard poos every 5 days and she screamed every time, I was afraid that she was going to get scared of pooing and she was starting to show those signs but no matter what I did nothing helped. I was finally told to try a mix of prune juice, apple juice and bran. She does not eat solids so I was unable to get bran into her but I give her her a small cup of 1 part prune juice, 1 part apple juice and 1 part water for morning tea every day and she has gone back to pooing every second day, they are a bit sloppy but it does not bother me that I have to clean it as she has not cried once .

Good luck, I hope you find something that works for you soon.