If u want to ship me the phone w/paid and addressed return mailer (I'm at 11790), Ill fix it for $20.
Most likely a charger/speaker youve been using is broken or crap quality. Ditch it and replace with quality ones. Ive seen plenty of bad charge ports and its always come down to a bad/broken cable/charger.
When u first buy an iphone, it comes with a year long warranty. If at any time during that year you have it swapped, the replacement phone comes with a 90 day warranty (or remainder of original warranty if u have over 90 days left on that). Any subsequent replacement automatically resets the 90 days. Applecare is 3 yrs, ~$40 on ebay, and definitely worth it. If youve bought a macbook within the past year, do yourself a favor and buy macbook applecare ASAP. One replacement battery alone (which you will need after 3 years) makes it worthwhile.