Hi Docter I Am Having Pain In My Back For

hi docter i am having pain in my back for last 20 days now initally i have taken amoxil and flagyl assuming that it was a gastric trouble then after the problem was not solved i went to a docter who give me omeprazole & an antacid for 3days my symptoms get a little bit better but when i went to him after 3 days he gave me iv inj 2 gm of ceftriaxone & ciprofloaxin 500mg in bd dose i have taken it but it doesnt suit me as it feels like my heart rate is dropping and i can not tolerate the medicine i went to another docter he gave me doxycycline 100 mg bd metronidazole 400mg od for motion that starts when i take antibiotic & omeprazole 20 mg daily in the morning my symptoms are a little bit better but the pain still persist a little bit i want to know what is my problem? & am i taking the right medicine this time?