Se me
 

Can se be used for saying something happened accidentally?
Para decir que algo ocurrió por casualidad, se puede usar se?

Se me di un golpe en la cabeza.
I accidentally hit my head.

Not, the sentence is a wrong, the word SE ME is used when you need to say some that happened you before in the past for example, Se me perdio la pelota.

But in your previous post you have said Se me di un golpe en la cabeza the proper sentence is bad builted, it would to be write so, Me di un golpe en la cabeza.

I will give you other example of the use of the word Se me.

These are another examples: Se me perdio las llaves, Se me olvido ir a la escuela.

I will try to translate the sentence in English.

I lost the keys, I forgot to go to the School.

I hope my examples will be useful for you.

Yes, se is used to say something happened by accident.
Se me rompió la silla. = The chair (accidentally) broke.
The last examples that Crotalito gave are also good examples.

???????
 

Por qué es okay decir Se me rompió la silla pero no okay decir Se me di un golpe en la cabeza.?

The reason is because se has to agree with the conjugated verb.

Se rompió la silla. The chair broke.
Se cayó el vaso. The glass fell.
Se perdieron las llaves. The keys were lost.

Se me rompió la silla. The chair broke on me.
Se me cayó el vaso. I dropped the glass.
Se me perdieron las llaves. I lost the keys.

The se always agrees with a verb in the third person singular or plural.

Se dio un golpe. He hit himself.
Me di un golpe. I hit myself.

Here's the formula for the "reflexive 'se' with an unplanned occurrence" construction:
se +
indirect object pronoun +
3rd-person preterite-tense verb that agrees in number with the subject +
subject

Here is a sample sentence:

Se me rompió el plato.
Subject = el plato
Verb = rompió
Object = me
(Literal translation: The plate broke on me.)

Contrast that with the English translation:

I broke the plate.
Subject = I
Verb = broke
Object = the plate

The Spanish don't take the blame for something that was unplanned; the subject, not the person (the object), did something totally out of the ordinary and the person was an innocent bystander. It's the same as when we say things like it slipped my mind or the glass slipped through my fingers.

Se me olvidó ir a la clase.
= I forgot to go to class.
Literally: Going to class forgot me.
Figuratively: Going to class slipped my mind.

Se me cayeron los vasos.
= I dropped the glasses.
Literally: The glasses dropped from me.
Figuratively: The glasses slipped through my fingers.

The reason you can't use the 'unplanned occurrence' construction when you hit your head on something is because you have to take the blame for it. :D
I'm partly joking. There are only certain verbs that are 'eligible' for this construction (and some of them take on a new meaning when utilized):
acabarse (to run out of)
apagarse (to go out on, to turn off on)
caerse (to drop from)
ocurrirse (to dawn on, to realize, to occur to)
olvidarse (to forget)
pararse (to stop on, to quit on)
perderse (to lose)
quedarse (to leave behind)
romperse (to break)

Se nos acabó la gasolina, y se nos paró el coche.
= We ran out of gasoline, and the car quit running.

Cmos, Do you understand that?

I would never say it but would it be correct to say Se me golpió mi cabeza? (instead of me golpeé la cabeza)

Se me golpeó la cabeza appears a couple of times on the Internet, but I wouldn't think it's grammatically correct. Me golpeé la cabeza is a good way to say it and you'll find a good amount of hits for that.

El objeto inanimado tiene la culpa en lugar de la persona.
Me gusta ese concepto.
Todo el mundo se explica (explican?) con perfección.