Since right lower quadrant pain may be due to many reasons , but in your case as ultrasound
and C T Scan shows nothing abnormal so need not to worry .
The cause of concern is ovarian cyst
, usually cyst in few cases ( mostly ) develops excruciating pain at the site of location.
The same pain is in your case.
Since you are 45 years old so it might happen that this bother you some more time.
Get in blood for L H/F S H ratio, estradiol ( estrogen ) , androgen level for further assessment of ovarian cyst.
Get in one more ultrasound of ovarian follicle
If you don't have other symptoms of PCOD ( cyst) then wait for sometimes ,
take pain killers as sometimes cyst resolves spontaneously with conservative treatment ( drugs).
For stomach you can take antacid with pantoprazole
after your treating doctor advice