An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage.

The inability to communicate verbally does not negate the possibility that an individual is experiencing pain and is in need of appropriate pain-relieving treatment. Notes: Pain is always subjective. Each individual learns the application of the word through experiences related to injury in early life.

Biologists recognize that those stimuli which cause pain are liable to damage tissue. Accordingly, pain is that experience we associate with actual or potential tissue damage.

It is unquestionably a sensation in a part or parts of the body, but it is also always unpleasant and therefore also an emotional experience. Experiences which resemble pain but are not unpleasant, e.g., pricking, should not be called pain.

Unpleasant abnormal experiences (dysesthesias) may also be pain but are not necessarily so because, subjectively, they may not have the usual sensory qualities of pain.

Please check http://www.webmd.com/pain-management/guide/default.htm for pain management and pain treatment. It includes all pain management methods. But it lack of complimentary therapy. For therapy, please check http://www.usadruglist.org/PainComplementaryTherapy/index.html.  The above links include following fields:

What is Pain Management
Pain Basics
What Is Chronic Pain?
Learn to Manage Your Rheumatoid Arthritis Pain
Causes
What Causes Chronic Pain?
Nerve Pain
Burns & Pain
Compressed Nerve (Pinched Nerve)
Are You at Risk?
Chronic Pain Conditions
Baby Boomers’ Aches & Pains
Related Guide: Joint Pain and Aging
Symptoms & Types
Symptoms
Back Fractures and Pain
Related Web Site: Effects of Chronic Pain
Tool: Is Neck and Back Pain Affecting Your Life?
Types
Chronic Knee & Joint Pain
Related Guide: Back Pain
Chronic Neck & Shoulder Pain
Whiplash
Chronic Muscle Pain
Muscle Pain
Temporomandibular (TMD) Disorders
Trigeminal Neuralgia
Shingles Pain (Postherpetic Neuralgia)
Related Guide: Sciatica Pain
Arachnoiditis: Spinal Pain
Complex Regional Pain Syndrome
Central Pain Syndrome
Phantom Limb Pain
Diabetes-Related Nerve Pain (Neuropathy)
Depression, Anxiety & Pain
Diagnosis & Tests
Diagnosis
Related Guide: Time to Call a Chronic Pain Doctor?
Related Guide: Doctors Who Treat Pain
10 Questions to Ask Your Doctor
Tests
Diagnosing Pain
Related Guide: Exams & Tests for Chronic Pain
Related Web Site: Quality-of-Life Scale for Pain
Treatment & Care
Treatment
Pain Management: Treatment Overview
Related Guide: Low Back Pain Treatment
Related Web Site: Chronic Pain Management
How Is Pain Treated?
Related Web Site: Finding the Right Pain Reliever
Related Web Site: Natural Pain Relief
Related Web Site: What Is Chiropractic?
Spine Pain and Treatments
Related Web Site: Cancer Pain: Myths and Misconceptions
Pain & Alternative Therapy
Pain Medications: OTC and Prescription
Narcotic Pain Medications
Nerve Block Injections and Pain (Local Anesthesia)
Related Guide: Trigger Point Injections
Related Guide: Spinal Cord Stimulation
Spinal Drug Delivery Systems
Patient-Controlled Analgesia (PCA) Pump
Related Guide: TENS (Electrothermal Therapy)
Bioelectric Therapy for Pain
Related Guide: Surgery & Pain
Advanced Reading: Treating Cancer Pain
Advanced Reading: Cancer, Elderly & Pain Medications
Care
Chronic Pain Control: Pain Relief Without Pills
Related Guide: Chronic Pain & Lifestyle Changes
Video: Back Pain Relief: Acupuncture
Chronic Pain Help: Exercise & Arthritis Pain
Pain & Drug Addiction
Palliative Care
Your Pain Treatment Agreement
Related Guide: Cancer Pain Control
Living & Managing
Living and Coping
Coping With Chronic Pain
Related Web Site: Stress Relief & Relaxation Techniques
Related Web Site: Sexual Intimacy
Related Web Site: Chronic Pain & Patients’ Rights
Personal Stories
Pain Management: Personal Stories
Support & Resources
Support
Pain Management Support
Resources
Pain Management Resources
Related Web Site: American Chronic Pain Association
Related Web Site: American Pain Foundation
Related Web Site: Find-a-Doctor and More
Related Web Site: The National Pain Foundation
Related Web Site: The Arthritis Foundation
Related Web Site: Related Web Site: National Headache Foundation
Related Web Site: The Neuropathy Association
Related Guide: Pain Medicine Organizations
Related Web Site: Pain Information