I Recently ( 7 Weeks Ago) Had My Gallbladder Removed,

i recently ( 7 weeks ago) had my gallbladder removed, since this I have had a constant chest pain mid/upper sternum area. I have been to the ER and all blood tests and ct scans show everything is normal. had a ekg and my heart was totally fine. My Gi doctor put my on Omeprazole ( I started this sunday) I still am having constant chest discomfort/pain and I do notice it work when leaning forward. I did not have this issue before surgery. Im being told this is GERD. if this is the case, how long will it take for the PPI to kick in? im trying to remain optimistic (as my GI doctor thinks "in time" this will clear up. whats you opinion. I just want to be well again!!! im 26y/o female, no previous health conditions ever!