can someone tell me the reason why Aphrodite and Hera were feuding? was it because they didn't want Aeneas to make to Italy?

Aphrodite and Hera often feud because Aphrodite is the symbol of love and Hera is the symbol of war. In mythology they often used to portray conflict.

so they fought in Aeneid because they always do?

... and because Vergil wrote this to emphasize a connection between the classical Greek culture and the new Roman culture.

http://en.wikipedia.org/wiki/Aeneid

The feud between Aphrodite and Hera is rooted in a broader conflict known as the Trojan War. While their rivalry does involve Aeneas, it is not the sole reason behind their feud.

To understand this, we need to go back to a judgment of Paris, a prince of Troy. According to Greek mythology, Paris was asked to award a golden apple to the most beautiful goddess among Aphrodite, Hera, and Athena. Paris chose Aphrodite, who promised him the love of the most beautiful woman, Helen.

Helen, however, was already married to Menelaus, the king of Sparta. When Helen eloped with Paris to Troy, Menelaus sought revenge and led a coalition of Greek states to siege Troy, thus starting the Trojan War. Aeneas, on the other hand, was a Trojan prince and a son of Aphrodite, who played a significant role in the war.

Now, as for the feud between Aphrodite and Hera, it largely stems from their support of different sides in the Trojan War. Hera, being the queen of the gods and the wife of Zeus, favored the Greeks. Aphrodite, as the mother of Aeneas and a supporter of the Trojans, was in opposition to Hera's interests.

While it is true that Aeneas plays a vital role in the mythology and that his journey to Italy is a significant part of his story, the feud between Aphrodite and Hera cannot be solely attributed to this. It is a result of their opposing loyalties during the Trojan War and the broader conflicts between the gods.