Sounds like a typical case of Generalized Anxiety Disorder and OCD. (really)
Have you seen a therapist? Been on any medications for OCD or anxiety disorder? I feel terrible that you've been going through this for so long with no help!
Read the fact sheet from the NIH link below. GAD has tons of very real physical - sometimes debilitating - symptoms.
http://www.nimh.nih.gov/health/topics/generalized-anxiety-disorder-gad/index.shtml
That lump in the throat feeling is called "globus hystericus" and it's a well known sign of anxiety disorder. It may be related to muscle tension.
