It's pretty common for stuttering to co-occur with something else. For about half of people who stutter, there is some co-occurring condition. However, it can make both diagnosis and treatment more complicated than the "common garden variety" stutterers, where there is just the stuttering and nothing else. What you might find is that some of the therapy techniques for developmental stuttering don't work as well for the type of stuttering you've got. And some might work better. You might need to experiment a bit. So, don't feel bad if you're trying stuff and it isn't working. Sometimes it can help if you change what you are hearing (altered auditory feedback) – that can be good for phone calls, since the listener can't see that you're using an auditory feedback device. You can get apps for your phone (iOS/Android) which will change what you hear. Alternatively, you can try prolonging syllables. Either prolong syllables when you think you'll stutter (called stuttering modification therapy) or prolong all the syllables (fluency shaping).