Is heroin death painful

Yes; heroin belongs to class of drugs called opiates. In fact, its chemical name is diacetyl-morphine. Heroin provides higher pain-relief than morphine, although less than that of intravenously injected fentanyl (which is a stronger opiate, or synthetic opiate to be more specific, but it is usually only used for injection during surgery to induce anesthesia and for post-operative pain while the patient is still hospitalized).

Heroin is a morphine-derivative, and therefore provides the same relief and acts in the exact same area of the brain (acting as a mu-opioid receptor agonist); albeit being more potent than morphine itself since it penetrates the brain more quickly. Heroin's analgesic effects are identical to high-potency opiates, semi-synthetic opiates, & opioids (it is most similar in its duration of action and potency to fentanyl and hydromorphone). Its adverse effects are mainly due to the additives found in heroin due its unregulated sale on the black-market--potentially causing stroke, heart attack, infection, and/or liver-damage when injected. Additionally, the lifestyle of black-market, illicit drug users also may attribute to some of the indirect adverse effects associated with heroin use.

Heroin is still legal for use in pain relief in a few countries. Although due to increased abuse (due to its "rush" effect when injected), heroin was perceived as being of higher abuse potential than other opiates; even though new opiates, especially fentanyl, have higher euphoric and analgesic potency than heroin.