Thanks for the query
It is unlikely that it is because if the drug as you have been on it for several months prior to it.
The stomach pain could be either gastritis
or secondary to constipation
itself. I advice you to take Syp lactulose
10 ml at night for the constipation and tab pantoprazole
40 for the pain abdomen, if it still persists or becomes more severe please approach a physician
I hope I was of help