Chris Matthews, 63, fast talking star of MSNBC’s Hardball, told his staff last night he will not be standing for the Pennsylvania Senate seat. A former aide to House speaker Tip O’Neill, Matthews, a Democrat who admitted that the prospect of an Obama presidency sent “a shiver up my leg,” has been toying with a run at the Senate from his native state for much of the last year. The speculation he would challenge the sitting Republican, Arlen Specter, was fueled by rumors that NBC was planning to ask him to continue his political jousting show but wanted him to take a drastic pay cut — from $5 million a year to about $1 million. A network executive said discussions with Matthews for a new contract were continuing.