Im new to APEX and i have a trigger that is suppose to calculate a total score using 6 fields.  If any of the data in those 6 fields gets updated I want the Trigger to recalcuate the score.  But my current code is not updating.  I have two issues

1) After I deployed the code the APEX trigger didnt do the calculation.  Why is this? 
2) After I made a change to one of the 6 data points the Trigger still didnt execute.  Why is this?

Could someone help look at the code I have and provide some recommeneded changes.  (just note I am new so some of the terms I may not understand if you would make any code changes can you show me the before and after change).  

trigger Health_Score_Calculation_New on Account (before insert) {
  if(Trigger.isBefore)
  {
    if (Trigger.isInsert || Trigger.isUpdate)
     {
       for(Account cob : trigger.new)

         {
             if(cob.Days_With_No_Activity__c!=null){
            //   cob.Days_With_No_Activity__c= 100 ;
             
             
            cob.Score__c = (cob.Implementation__c * 0.15) + 
                           (cob.Migration_In_Progress__c * 0.20) + 
                           (cob.Days_With_No_Activity__c * 0.15) + 
                           (cob.Contact_New2__c * 0.15) + 
                           (cob.Contact_Left2__c * 0.15) + 
                           (cob.Issues__c * 0.20) ;
                           }
           }
       }
    }
}