Both of the sentences you provided are grammatically correct, but they have slightly different nuances in terms of tense and tone. "I have a hectic schedule today, I’m gonna shoot some videos." This sentence uses the present tense ("have") to indicate that your schedule for the day is busy, and you're planning to shoot some videos later. It's a straightforward statement of your schedule. "I’m having a hectic schedule today, I’m gonna shoot some videos." This sentence uses the present continuous tense ("having") to emphasize the ongoing nature of your busy schedule. It adds a sense of immediacy and current experience to your statement. Both versions can be used, but the choice between them depends on the specific nuance you want to convey. If you want to emphasize that your schedule is currently busy and you're in the midst of it, the second sentence is a slightly stronger choice. If you want to communicate your schedule's busyness in a more general sense, the first sentence works well.