I was diagnosed with strep without a culture test done. how long before penicillin decreases the pain? might i be resistant to penicillin?

Strep: If indeed a strep throat you should get relief in 24 hrs. However if not a strep throat the antibiotic will not help at all. It is unlikely that there is resistance involved.

Strep throat: There is substantial data to suggest that antibiotic treatment for grp a strep pharyngitis may not alter the clinical manifestations and that patients get symptomatically better with or without them. The purpose of penicillin (or other antibiotics) is to prevent the development of post=streptococcal complications like acute rheumatic fever.

Depends: Some strains of pathogens have mutated to be resistant to penicillin. When indicated, use of antibiotics is wonderful, and has changed medicine since the mid 20th century. I do have a problem with indiscriminate use of them, or diagnosis by reaction to them. Over or improper rx of antibiotics has contributed to the very important problem of bacterial resistance.