Pain is a blessing

I've been thinking about these questions a lot: Why are we in pain when somebody hurts us or when we fall ? Why do we have to feel pain ?

According to Jane A. Smith (Dept. of Biomedical Sciences, University at Birmingham), animals experience something that analogous to pain in human. And even surprising, she mentioned that not only vertebrate, but also invertebrates are capable of "nociception" or responding to noxious or aversive stimuli (such as: contact with noxius chemicals, mechanical interference, and electric shock). And, in general their response to these aversive stimuli is like vertebrates: escape or withdraw, hence they can avoid any damage made by those aversive stimuli. Smith also mentioned that earthworms can produce the same opioid substances as human. Injection of one of these substances can induce escaping behavior for the worms. As for human, pain is more than simple reflexes of noxious responses to aversive stimuli, because it also involves more emotional and physiological components. There is an experience of feeling unpleasant that sometimes we call as pain.

Back to the question, pain for us may be just a response to something that harms us. The pain may act as a warning system to avoid the cause of it. We feel something unpleasant. We are in pain. We suffer. Sometimes we even curse the pain itself and the cause of it. After we fall or we are hurted, we should not concentrate too much in the pain. Just deal with it for a while, cry if you need to, and then go on with your life. The pain will be gone soon or later.

My point is: if we cannot feel pain, I guess we'll never learn...

Reference: Smith, J.A. 1991. A question in pain in invertebrates. ILAR journal 33(1-2)