Vancomycin is usually given intravenously, as an infusion, and can cause tissue necrosis and phlebitis at the injection site if given too rapidly. Pain at site of injection is indeed a common adverse event. One of the side-effects is red man syndrome, an idiosyncratic reaction to bolus caused by histamine release. Some other side-effects of vancomycin are nephrotoxicity including kidney failure and interstitial nephritis, blood disorders including neutropenia, and deafness, which is reversible once therapy has stopped. Over 90% of the dose is excreted in the urine, therefore there is a risk of accumulation in patients with renal impairment, so therapeutic drug monitoring (TDM) is recommended.
Oral preparations of vancomycin are available, however they are not absorbed from the lumen of the gut, so are of no use in treating systemic infections.  The oral preparations are formulated for the treatment of infections within the gastrointestinal tract, Clostridium difficile, for example.