What Causes Weakness And Body Pain Despite A Normal Blood Work?

I am a 63 year old female. For the past four or more months I have been experiencing extreme weakness and for the past couple of weeks I have been feeling ill with chills and body aches. My Dr had me have some blood work done and he gave me the results yesterday. My thyroid, liver, kidneys, vitamins and mineral intake, cholesterol was all good. He said my white blood count was a little elevated and would check it again in three months. My blood work had also been elevated like a year or so ago but my Dr. didnt seem concerned I guess and I had forgot about it as my husband was ill and passed a year ago next month. Question, Should I be concerned about my elevated white blood count and is that why I am feeling weak and not feeling well? I feel really achy and weak today and tired of feeling this way. My mother had small cell nonhodgekins lymphoma and I worry about that.