SAYING YA RASOOLALLAH صلی اللہ علیہ وسلم
The sensitive issue of whether or not Muslims can say the words 'Ya Rasool Allah' or Ya Muhammad! [May Allah bless him and grant him peace] needs to be clarified, since this issue divides the Muslim community and causes a great deal of friction among the Muslims throughout the world. Basically, there appears to be what we could label as two schools of thought. One insists that saying that stating Ya Rasul Allah is 'shirk' and that any Muslim proclaiming it in fact goes outside the pale of Islam. Now the other School believes that it is indeed permissible to say so based on evidences from the Salaf, and the tafsirs of later day scholars. However, they do not insist that one must proclaim this or that it is even a fard to do so, rather, it is permissible to do so. This is, and always has been, the stance of the Ahl al-Sunna.
Those who believe that it is impermissible to say Ya Muhammad! [May Allah bless him and grant him peace] not only say that there are no evidences to support the permissibility, but also believe that the prefix of Ya, can only be used when that person [who is being called upon] is present, as opposed to being absent. The proclamation of Ya Muhammad, or Ya Rasul Allah [May Allah bless him and grant him peace] is not an innovation [bid'a] that crept in after the first three generations, but contrary to modern misconceptions, was initiated and practiced within these generations, as we shall see, Allah willing. Also, the fact that the later generations did proclaim Ya Muhammad! [May Allah bless him and grant him peace] the death of the Prophet [May Allah bless him and grant him peace], did not prevent them in doing so, even though there were great distances between them and Madina.