I have 3 red (bites/rashes) biggest, bigger and big on my rib cage. a dr said shingles but i think bug bites (bed bugs?). i found zero bugs in my bed.

Topical antibiotics: Pain, redness, sometimes itching, blisters and a rash especially along a rib, that does not cross the midline either in the front or back, is very concerning and characteristic for shingles. Antiviral medication would best treat this. If it's just a localized area of redness and swelling, topical antibiotics may be helpful.

Probably are bites.: I couldn't be sure because I haven't taken a History and Physical on you but your description favors bug bites if there are no blisters and if they do not follow a nerve dermatone pattern.