Inosert is the brand name; the name of the medicine is sertraline. Similarly Zoloft is the brand name. It contains sertraline. Hence both the medicines are identical. If you have been taking Zoloft (sertraline) since the year 2000, by now you should have got used to its side effects.
Abdominal pain, dyspepsia and diarrhoea are known side effects of sertraline (whether you take Zoloft or Inosert brand).
Prilosec - a non-prescription product - contains omeprazole, which reduces acidity. You can safely try and see if it helps you.