Medicine forpain due to stone in stomach

My mother is 60 years .My mother was suffering from Abodominal pain in lower left side and some time centre part of stomach for last 2 days ( today there is no pain ) Today I went for her X-ray stomach .In X-ray report there is 2 very small round part in her lower right part of stomach. For past 3 month she was on calcium tablet due to pain in  lower back as suggested by Orthopaedic doctor. (1) Pls suggest me some  best general pain killer medicine for stomach pain ( also helps in stone related pain) (2) Is it necessary that person with stone in stomach will suffer from stomach pain continuously or pain may occur in stomach at some days gap? (3) If stone is seen in Lower right part of stomach then why pain is in Lower left part or centre part of stomach? (4) Does consuming Calcium tablet play a role in causing stone in stomach? Pls advise.