How can i turn off the chatter in my head? lately i find it hard to meditate or concentrate. can you offer advice if its psychological or medical?

Most likely: Psychological. Stress can make meditation and concentration harder. Practice. Also would be helpful to know where your mind goes.

See a psychiatrist: Diagnose the cause of the chatter & see if there are treatments to control it.

You might try a: different form of meditation--one that allows chatter and actually uses it to de-stress. Look at Zazen (free) or even TM (if you have lots of $). What other conditions cause mind chatter? Hangovers, drug side-effects, mania or even agitated depression, bad diet (allergies to crud food), little or no exercise, no sex life...Try a psychologist who meditates and see where this goes...